initial import of NetBSD tree

28 files changed, 17096 insertions, 0 deletions

diff --git a/gnu/usr.bin/diff/COPYING b/gnu/usr.bin/diff/COPYING
new file mode 100644
index 00000000000..a43ea2126fb
--- /dev/null
+++ b/gnu/usr.bin/diff/COPYING
@@ -0,0 +1,339 @@
+		    GNU GENERAL PUBLIC LICENSE
+		       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.
+                          675 Mass Ave, Cambridge, MA 02139, USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+			    Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Library General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+		    GNU GENERAL PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term "modification".)  Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope.  The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+  2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+    a) You must cause the modified files to carry prominent notices
+    stating that you changed the files and the date of any change.
+
+    b) You must cause any work that you distribute or publish, that in
+    whole or in part contains or is derived from the Program or any
+    part thereof, to be licensed as a whole at no charge to all third
+    parties under the terms of this License.
+
+    c) If the modified program normally reads commands interactively
+    when run, you must cause it, when started running for such
+    interactive use in the most ordinary way, to print or display an
+    announcement including an appropriate copyright notice and a
+    notice that there is no warranty (or else, saying that you provide
+    a warranty) and that users may redistribute the program under
+    these conditions, and telling the user how to view a copy of this
+    License.  (Exception: if the Program itself is interactive but
+    does not normally print such an announcement, your work based on
+    the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works.  But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+  3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+    a) Accompany it with the complete corresponding machine-readable
+    source code, which must be distributed under the terms of Sections
+    1 and 2 above on a medium customarily used for software interchange; or,
+
+    b) Accompany it with a written offer, valid for at least three
+    years, to give any third party, for a charge no more than your
+    cost of physically performing source distribution, a complete
+    machine-readable copy of the corresponding source code, to be
+    distributed under the terms of Sections 1 and 2 above on a medium
+    customarily used for software interchange; or,
+
+    c) Accompany it with the information you received as to the offer
+    to distribute corresponding source code.  (This alternative is
+    allowed only for noncommercial distribution and only if you
+    received the program in object code or executable form with such
+    an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it.  For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable.  However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+  4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+  5. You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+  6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions.  You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+  7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+  8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+  9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission.  For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this.  Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+			    NO WARRANTY
+
+  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+		     END OF TERMS AND CONDITIONS
+
+	Appendix: How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) 19yy  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+    Gnomovision version 69, Copyright (C) 19yy name of author
+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Library General
+Public License instead of this License.
diff --git a/gnu/usr.bin/diff/Makefile b/gnu/usr.bin/diff/Makefile
new file mode 100644
index 00000000000..3e9fa378732
--- /dev/null
+++ b/gnu/usr.bin/diff/Makefile
@@ -0,0 +1,11 @@
+#	$NetBSD: Makefile,v 1.8 1995/07/12 07:21:05 cgd Exp $
+
+PROG=	diff
+SRCS=	diff.c analyze.c cmpbuf.o io.c context.c ed.c normal.c util.c dir.c \
+	regex.c side.c ifdef.c version.c getopt.c getopt1.c
+
+CFLAGS+=-DHAVE_CONFIG_H -I${.CURDIR} -DPR_PROGRAM=\"/usr/bin/pr\"
+LDADD+=	-lgnumalloc
+DPADD+=	/usr/lib/libgnumalloc.a
+
+.include <bsd.prog.mk>
diff --git a/gnu/usr.bin/diff/analyze.c b/gnu/usr.bin/diff/analyze.c
new file mode 100644
index 00000000000..556d388c46a
--- /dev/null
+++ b/gnu/usr.bin/diff/analyze.c
@@ -0,0 +1,1084 @@
+/* Analyze file differences for GNU DIFF.
+   Copyright (C) 1988, 1989, 1992, 1993 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* The basic algorithm is described in:
+   "An O(ND) Difference Algorithm and its Variations", Eugene Myers,
+   Algorithmica Vol. 1 No. 2, 1986, pp. 251-266;
+   see especially section 4.2, which describes the variation used below.
+   Unless the --minimal option is specified, this code uses the TOO_EXPENSIVE
+   heuristic, by Paul Eggert, to limit the cost to O(N**1.5 log N)
+   at the price of producing suboptimal output for large inputs with
+   many differences.
+
+   The basic algorithm was independently discovered as described in:
+   "Algorithms for Approximate String Matching", E. Ukkonen,
+   Information and Control Vol. 64, 1985, pp. 100-118.  */
+
+#include "diff.h"
+#include "cmpbuf.h"
+
+extern int no_discards;
+
+static int *xvec, *yvec;	/* Vectors being compared. */
+static int *fdiag;		/* Vector, indexed by diagonal, containing
+				   1 + the X coordinate of the point furthest
+				   along the given diagonal in the forward
+				   search of the edit matrix. */
+static int *bdiag;		/* Vector, indexed by diagonal, containing
+				   the X coordinate of the point furthest
+				   along the given diagonal in the backward
+				   search of the edit matrix. */
+static int too_expensive;	/* Edit scripts longer than this are too
+				   expensive to compute.  */
+
+#define SNAKE_LIMIT 20	/* Snakes bigger than this are considered `big'.  */
+
+struct partition
+{
+  int xmid, ymid;	/* Midpoints of this partition.  */
+  int lo_minimal;	/* Nonzero if low half will be analyzed minimally.  */
+  int hi_minimal;	/* Likewise for high half.  */
+};
+
+static int diag PARAMS((int, int, int, int, int, struct partition *));
+static struct change *add_change PARAMS((int, int, int, int, struct change *));
+static struct change *build_reverse_script PARAMS((struct file_data const[]));
+static struct change *build_script PARAMS((struct file_data const[]));
+static void briefly_report PARAMS((int, struct file_data const[]));
+static void compareseq PARAMS((int, int, int, int, int));
+static void discard_confusing_lines PARAMS((struct file_data[]));
+static void shift_boundaries PARAMS((struct file_data[]));
+
+/* Find the midpoint of the shortest edit script for a specified
+   portion of the two files.
+
+   Scan from the beginnings of the files, and simultaneously from the ends,
+   doing a breadth-first search through the space of edit-sequence.
+   When the two searches meet, we have found the midpoint of the shortest
+   edit sequence.
+
+   If MINIMAL is nonzero, find the minimal edit script regardless
+   of expense.  Otherwise, if the search is too expensive, use
+   heuristics to stop the search and report a suboptimal answer.
+
+   Set PART->(XMID,YMID) to the midpoint (XMID,YMID).  The diagonal number
+   XMID - YMID equals the number of inserted lines minus the number
+   of deleted lines (counting only lines before the midpoint).
+   Return the approximate edit cost; this is the total number of
+   lines inserted or deleted (counting only lines before the midpoint),
+   unless a heuristic is used to terminate the search prematurely.
+
+   Set PART->LEFT_MINIMAL to nonzero iff the minimal edit script for the
+   left half of the partition is known; similarly for PART->RIGHT_MINIMAL.
+
+   This function assumes that the first lines of the specified portions
+   of the two files do not match, and likewise that the last lines do not
+   match.  The caller must trim matching lines from the beginning and end
+   of the portions it is going to specify.
+
+   If we return the "wrong" partitions,
+   the worst this can do is cause suboptimal diff output.
+   It cannot cause incorrect diff output.  */
+
+static int
+diag (xoff, xlim, yoff, ylim, minimal, part)
+     int xoff, xlim, yoff, ylim, minimal;
+     struct partition *part;
+{
+  int *const fd = fdiag;	/* Give the compiler a chance. */
+  int *const bd = bdiag;	/* Additional help for the compiler. */
+  int const *const xv = xvec;	/* Still more help for the compiler. */
+  int const *const yv = yvec;	/* And more and more . . . */
+  int const dmin = xoff - ylim;	/* Minimum valid diagonal. */
+  int const dmax = xlim - yoff;	/* Maximum valid diagonal. */
+  int const fmid = xoff - yoff;	/* Center diagonal of top-down search. */
+  int const bmid = xlim - ylim;	/* Center diagonal of bottom-up search. */
+  int fmin = fmid, fmax = fmid;	/* Limits of top-down search. */
+  int bmin = bmid, bmax = bmid;	/* Limits of bottom-up search. */
+  int c;			/* Cost. */
+  int odd = (fmid - bmid) & 1;	/* True if southeast corner is on an odd
+				   diagonal with respect to the northwest. */
+
+  fd[fmid] = xoff;
+  bd[bmid] = xlim;
+
+  for (c = 1;; ++c)
+    {
+      int d;			/* Active diagonal. */
+      int big_snake = 0;
+
+      /* Extend the top-down search by an edit step in each diagonal. */
+      fmin > dmin ? fd[--fmin - 1] = -1 : ++fmin;
+      fmax < dmax ? fd[++fmax + 1] = -1 : --fmax;
+      for (d = fmax; d >= fmin; d -= 2)
+	{
+	  int x, y, oldx, tlo = fd[d - 1], thi = fd[d + 1];
+
+	  if (tlo >= thi)
+	    x = tlo + 1;
+	  else
+	    x = thi;
+	  oldx = x;
+	  y = x - d;
+	  while (x < xlim && y < ylim && xv[x] == yv[y])
+	    ++x, ++y;
+	  if (x - oldx > SNAKE_LIMIT)
+	    big_snake = 1;
+	  fd[d] = x;
+	  if (odd && bmin <= d && d <= bmax && bd[d] <= x)
+	    {
+	      part->xmid = x;
+	      part->ymid = y;
+	      part->lo_minimal = part->hi_minimal = 1;
+	      return 2 * c - 1;
+	    }
+	}
+
+      /* Similarly extend the bottom-up search.  */
+      bmin > dmin ? bd[--bmin - 1] = INT_MAX : ++bmin;
+      bmax < dmax ? bd[++bmax + 1] = INT_MAX : --bmax;
+      for (d = bmax; d >= bmin; d -= 2)
+	{
+	  int x, y, oldx, tlo = bd[d - 1], thi = bd[d + 1];
+
+	  if (tlo < thi)
+	    x = tlo;
+	  else
+	    x = thi - 1;
+	  oldx = x;
+	  y = x - d;
+	  while (x > xoff && y > yoff && xv[x - 1] == yv[y - 1])
+	    --x, --y;
+	  if (oldx - x > SNAKE_LIMIT)
+	    big_snake = 1;
+	  bd[d] = x;
+	  if (!odd && fmin <= d && d <= fmax && x <= fd[d])
+	    {
+	      part->xmid = x;
+	      part->ymid = y;
+	      part->lo_minimal = part->hi_minimal = 1;
+	      return 2 * c;
+	    }
+	}
+
+      if (minimal)
+	continue;
+
+      /* Heuristic: check occasionally for a diagonal that has made
+	 lots of progress compared with the edit distance.
+	 If we have any such, find the one that has made the most
+	 progress and return it as if it had succeeded.
+
+	 With this heuristic, for files with a constant small density
+	 of changes, the algorithm is linear in the file size.  */
+
+      if (c > 200 && big_snake && heuristic)
+	{
+	  int best;
+
+	  best = 0;
+	  for (d = fmax; d >= fmin; d -= 2)
+	    {
+	      int dd = d - fmid;
+	      int x = fd[d];
+	      int y = x - d;
+	      int v = (x - xoff) * 2 - dd;
+	      if (v > 12 * (c + (dd < 0 ? -dd : dd)))
+		{
+		  if (v > best
+		      && xoff + SNAKE_LIMIT <= x && x < xlim
+		      && yoff + SNAKE_LIMIT <= y && y < ylim)
+		    {
+		      /* We have a good enough best diagonal;
+			 now insist that it end with a significant snake.  */
+		      int k;
+
+		      for (k = 1; xv[x - k] == yv[y - k]; k++)
+			if (k == SNAKE_LIMIT)
+			  {
+			    best = v;
+			    part->xmid = x;
+			    part->ymid = y;
+			    break;
+			  }
+		    }
+		}
+	    }
+	  if (best > 0)
+	    {
+	      part->lo_minimal = 1;
+	      part->hi_minimal = 0;
+	      return 2 * c - 1;
+	    }
+
+	  best = 0;
+	  for (d = bmax; d >= bmin; d -= 2)
+	    {
+	      int dd = d - bmid;
+	      int x = bd[d];
+	      int y = x - d;
+	      int v = (xlim - x) * 2 + dd;
+	      if (v > 12 * (c + (dd < 0 ? -dd : dd)))
+		{
+		  if (v > best
+		      && xoff < x && x <= xlim - SNAKE_LIMIT
+		      && yoff < y && y <= ylim - SNAKE_LIMIT)
+		    {
+		      /* We have a good enough best diagonal;
+			 now insist that it end with a significant snake.  */
+		      int k;
+
+		      for (k = 0; xv[x + k] == yv[y + k]; k++)
+			if (k == SNAKE_LIMIT - 1)
+			  {
+			    best = v;
+			    part->xmid = x;
+			    part->ymid = y;
+			    break;
+			  }
+		    }
+		}
+	    }
+	  if (best > 0)
+	    {
+	      part->lo_minimal = 0;
+	      part->hi_minimal = 1;
+	      return 2 * c - 1;
+	    }
+	}
+
+      /* Heuristic: if we've gone well beyond the call of duty,
+	 give up and report halfway between our best results so far.  */
+      if (c >= too_expensive)
+	{
+	  int fxybest, fxbest;
+	  int bxybest, bxbest;
+
+	  fxbest = bxbest = 0;  /* Pacify `gcc -Wall'.  */
+
+	  /* Find forward diagonal that maximizes X + Y.  */
+	  fxybest = -1;
+	  for (d = fmax; d >= fmin; d -= 2)
+	    {
+	      int x = min (fd[d], xlim);
+	      int y = x - d;
+	      if (ylim < y)
+		x = ylim + d, y = ylim;
+	      if (fxybest < x + y)
+		{
+		  fxybest = x + y;
+		  fxbest = x;
+		}
+	    }
+
+	  /* Find backward diagonal that minimizes X + Y.  */
+	  bxybest = INT_MAX;
+	  for (d = bmax; d >= bmin; d -= 2)
+	    {
+	      int x = max (xoff, bd[d]);
+	      int y = x - d;
+	      if (y < yoff)
+		x = yoff + d, y = yoff;
+	      if (x + y < bxybest)
+		{
+		  bxybest = x + y;
+		  bxbest = x;
+		}
+	    }
+
+	  /* Use the better of the two diagonals.  */
+	  if ((xlim + ylim) - bxybest < fxybest - (xoff + yoff))
+	    {
+	      part->xmid = fxbest;
+	      part->ymid = fxybest - fxbest;
+	      part->lo_minimal = 1;
+	      part->hi_minimal = 0;
+	    }
+	  else
+	    {
+	      part->xmid = bxbest;
+	      part->ymid = bxybest - bxbest;
+	      part->lo_minimal = 0;
+	      part->hi_minimal = 1;
+	    }
+	  return 2 * c - 1;
+	}
+    }
+}
+
+/* Compare in detail contiguous subsequences of the two files
+   which are known, as a whole, to match each other.
+
+   The results are recorded in the vectors files[N].changed_flag, by
+   storing a 1 in the element for each line that is an insertion or deletion.
+
+   The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
+
+   Note that XLIM, YLIM are exclusive bounds.
+   All line numbers are origin-0 and discarded lines are not counted.
+ 
+   If MINIMAL is nonzero, find a minimal difference no matter how
+   expensive it is.  */
+
+static void
+compareseq (xoff, xlim, yoff, ylim, minimal)
+     int xoff, xlim, yoff, ylim, minimal;
+{
+  int * const xv = xvec; /* Help the compiler.  */
+  int * const yv = yvec;
+
+  /* Slide down the bottom initial diagonal. */
+  while (xoff < xlim && yoff < ylim && xv[xoff] == yv[yoff])
+    ++xoff, ++yoff;
+  /* Slide up the top initial diagonal. */
+  while (xlim > xoff && ylim > yoff && xv[xlim - 1] == yv[ylim - 1])
+    --xlim, --ylim;
+
+  /* Handle simple cases. */
+  if (xoff == xlim)
+    while (yoff < ylim)
+      files[1].changed_flag[files[1].realindexes[yoff++]] = 1;
+  else if (yoff == ylim)
+    while (xoff < xlim)
+      files[0].changed_flag[files[0].realindexes[xoff++]] = 1;
+  else
+    {
+      int c;
+      struct partition part;
+
+      /* Find a point of correspondence in the middle of the files.  */
+
+      c = diag (xoff, xlim, yoff, ylim, minimal, &part);
+
+      if (c == 1)
+	{
+	  /* This should be impossible, because it implies that
+	     one of the two subsequences is empty,
+	     and that case was handled above without calling `diag'.
+	     Let's verify that this is true.  */
+	  abort ();
+#if 0
+	  /* The two subsequences differ by a single insert or delete;
+	     record it and we are done.  */
+	  if (part.xmid - part.ymid < xoff - yoff)
+	    files[1].changed_flag[files[1].realindexes[part.ymid - 1]] = 1;
+	  else
+	    files[0].changed_flag[files[0].realindexes[part.xmid]] = 1;
+#endif
+	}
+      else
+	{
+	  /* Use the partitions to split this problem into subproblems.  */
+	  compareseq (xoff, part.xmid, yoff, part.ymid, part.lo_minimal);
+	  compareseq (part.xmid, xlim, part.ymid, ylim, part.hi_minimal);
+	}
+    }
+}
+
+/* Discard lines from one file that have no matches in the other file.
+
+   A line which is discarded will not be considered by the actual
+   comparison algorithm; it will be as if that line were not in the file.
+   The file's `realindexes' table maps virtual line numbers
+   (which don't count the discarded lines) into real line numbers;
+   this is how the actual comparison algorithm produces results
+   that are comprehensible when the discarded lines are counted.
+
+   When we discard a line, we also mark it as a deletion or insertion
+   so that it will be printed in the output.  */
+
+static void
+discard_confusing_lines (filevec)
+     struct file_data filevec[];
+{
+  unsigned int f, i;
+  char *discarded[2];
+  int *equiv_count[2];
+  int *p;
+
+  /* Allocate our results.  */
+  p = (int *) xmalloc ((filevec[0].buffered_lines + filevec[1].buffered_lines)
+		       * (2 * sizeof (int)));
+  for (f = 0; f < 2; f++)
+    {
+      filevec[f].undiscarded = p;  p += filevec[f].buffered_lines;
+      filevec[f].realindexes = p;  p += filevec[f].buffered_lines;
+    }
+
+  /* Set up equiv_count[F][I] as the number of lines in file F
+     that fall in equivalence class I.  */
+
+  p = (int *) xmalloc (filevec[0].equiv_max * (2 * sizeof (int)));
+  equiv_count[0] = p;
+  equiv_count[1] = p + filevec[0].equiv_max;
+  bzero (p, filevec[0].equiv_max * (2 * sizeof (int)));
+
+  for (i = 0; i < filevec[0].buffered_lines; ++i)
+    ++equiv_count[0][filevec[0].equivs[i]];
+  for (i = 0; i < filevec[1].buffered_lines; ++i)
+    ++equiv_count[1][filevec[1].equivs[i]];
+
+  /* Set up tables of which lines are going to be discarded.  */
+
+  discarded[0] = xmalloc (sizeof (char)
+			  * (filevec[0].buffered_lines
+			     + filevec[1].buffered_lines));
+  discarded[1] = discarded[0] + filevec[0].buffered_lines;
+  bzero (discarded[0], sizeof (char) * (filevec[0].buffered_lines
+					+ filevec[1].buffered_lines));
+
+  /* Mark to be discarded each line that matches no line of the other file.
+     If a line matches many lines, mark it as provisionally discardable.  */
+
+  for (f = 0; f < 2; f++)
+    {
+      unsigned int end = filevec[f].buffered_lines;
+      char *discards = discarded[f];
+      int *counts = equiv_count[1 - f];
+      int *equivs = filevec[f].equivs;
+      unsigned int many = 5;
+      unsigned int tem = end / 64;
+
+      /* Multiply MANY by approximate square root of number of lines.
+	 That is the threshold for provisionally discardable lines.  */
+      while ((tem = tem >> 2) > 0)
+	many *= 2;
+
+      for (i = 0; i < end; i++)
+	{
+	  int nmatch;
+	  if (equivs[i] == 0)
+	    continue;
+	  nmatch = counts[equivs[i]];
+	  if (nmatch == 0)
+	    discards[i] = 1;
+	  else if (nmatch > many)
+	    discards[i] = 2;
+	}
+    }
+
+  /* Don't really discard the provisional lines except when they occur
+     in a run of discardables, with nonprovisionals at the beginning
+     and end.  */
+
+  for (f = 0; f < 2; f++)
+    {
+      unsigned int end = filevec[f].buffered_lines;
+      register char *discards = discarded[f];
+
+      for (i = 0; i < end; i++)
+	{
+	  /* Cancel provisional discards not in middle of run of discards.  */
+	  if (discards[i] == 2)
+	    discards[i] = 0;
+	  else if (discards[i] != 0)
+	    {
+	      /* We have found a nonprovisional discard.  */
+	      register int j;
+	      unsigned int length;
+	      unsigned int provisional = 0;
+
+	      /* Find end of this run of discardable lines.
+		 Count how many are provisionally discardable.  */
+	      for (j = i; j < end; j++)
+		{
+		  if (discards[j] == 0)
+		    break;
+		  if (discards[j] == 2)
+		    ++provisional;
+		}
+
+	      /* Cancel provisional discards at end, and shrink the run.  */
+	      while (j > i && discards[j - 1] == 2)
+		discards[--j] = 0, --provisional;
+
+	      /* Now we have the length of a run of discardable lines
+		 whose first and last are not provisional.  */
+	      length = j - i;
+
+	      /* If 1/4 of the lines in the run are provisional,
+		 cancel discarding of all provisional lines in the run.  */
+	      if (provisional * 4 > length)
+		{
+		  while (j > i)
+		    if (discards[--j] == 2)
+		      discards[j] = 0;
+		}
+	      else
+		{
+		  register unsigned int consec;
+		  unsigned int minimum = 1;
+		  unsigned int tem = length / 4;
+
+		  /* MINIMUM is approximate square root of LENGTH/4.
+		     A subrun of two or more provisionals can stand
+		     when LENGTH is at least 16.
+		     A subrun of 4 or more can stand when LENGTH >= 64.  */
+		  while ((tem = tem >> 2) > 0)
+		    minimum *= 2;
+		  minimum++;
+
+		  /* Cancel any subrun of MINIMUM or more provisionals
+		     within the larger run.  */
+		  for (j = 0, consec = 0; j < length; j++)
+		    if (discards[i + j] != 2)
+		      consec = 0;
+		    else if (minimum == ++consec)
+		      /* Back up to start of subrun, to cancel it all.  */
+		      j -= consec;
+		    else if (minimum < consec)
+		      discards[i + j] = 0;
+
+		  /* Scan from beginning of run
+		     until we find 3 or more nonprovisionals in a row
+		     or until the first nonprovisional at least 8 lines in.
+		     Until that point, cancel any provisionals.  */
+		  for (j = 0, consec = 0; j < length; j++)
+		    {
+		      if (j >= 8 && discards[i + j] == 1)
+			break;
+		      if (discards[i + j] == 2)
+			consec = 0, discards[i + j] = 0;
+		      else if (discards[i + j] == 0)
+			consec = 0;
+		      else
+			consec++;
+		      if (consec == 3)
+			break;
+		    }
+
+		  /* I advances to the last line of the run.  */
+		  i += length - 1;
+
+		  /* Same thing, from end.  */
+		  for (j = 0, consec = 0; j < length; j++)
+		    {
+		      if (j >= 8 && discards[i - j] == 1)
+			break;
+		      if (discards[i - j] == 2)
+			consec = 0, discards[i - j] = 0;
+		      else if (discards[i - j] == 0)
+			consec = 0;
+		      else
+			consec++;
+		      if (consec == 3)
+			break;
+		    }
+		}
+	    }
+	}
+    }
+
+  /* Actually discard the lines. */
+  for (f = 0; f < 2; f++)
+    {
+      char *discards = discarded[f];
+      unsigned int end = filevec[f].buffered_lines;
+      unsigned int j = 0;
+      for (i = 0; i < end; ++i)
+	if (no_discards || discards[i] == 0)
+	  {
+	    filevec[f].undiscarded[j] = filevec[f].equivs[i];
+	    filevec[f].realindexes[j++] = i;
+	  }
+	else
+	  filevec[f].changed_flag[i] = 1;
+      filevec[f].nondiscarded_lines = j;
+    }
+
+  free (discarded[0]);
+  free (equiv_count[0]);
+}
+
+/* Adjust inserts/deletes of identical lines to join changes
+   as much as possible.
+
+   We do something when a run of changed lines include a
+   line at one end and have an excluded, identical line at the other.
+   We are free to choose which identical line is included.
+   `compareseq' usually chooses the one at the beginning,
+   but usually it is cleaner to consider the following identical line
+   to be the "change".  */
+
+int inhibit;
+
+static void
+shift_boundaries (filevec)
+     struct file_data filevec[];
+{
+  int f;
+
+  if (inhibit)
+    return;
+
+  for (f = 0; f < 2; f++)
+    {
+      char *changed = filevec[f].changed_flag;
+      char const *other_changed = filevec[1-f].changed_flag;
+      int const *equivs = filevec[f].equivs;
+      int i = 0;
+      int j = 0;
+      int i_end = filevec[f].buffered_lines;
+
+      while (1)
+	{
+	  int runlength, start, corresponding;
+
+	  /* Scan forwards to find beginning of another run of changes.
+	     Also keep track of the corresponding point in the other file.  */
+
+	  while (i < i_end && changed[i] == 0)
+	    {
+	      while (other_changed[j++])
+		continue;
+	      i++;
+	    }
+
+	  if (i == i_end)
+	    break;
+
+	  start = i;
+
+	  /* Find the end of this run of changes.  */
+
+	  while (changed[++i])
+	    continue;
+	  while (other_changed[j])
+	    j++;
+
+	  do
+	    {
+	      /* Record the length of this run of changes, so that
+		 we can later determine whether the run has grown.  */
+	      runlength = i - start;
+
+	      /* Move the changed region back, so long as the
+		 previous unchanged line matches the last changed one.
+		 This merges with previous changed regions.  */
+
+	      while (start && equivs[start - 1] == equivs[i - 1])
+		{
+		  changed[--start] = 1;
+		  changed[--i] = 0;
+		  while (changed[start - 1])
+		    start--;
+		  while (other_changed[--j])
+		    continue;
+		}
+
+	      /* Set CORRESPONDING to the end of the changed run, at the last
+		 point where it corresponds to a changed run in the other file.
+		 CORRESPONDING == I_END means no such point has been found.  */
+	      corresponding = other_changed[j - 1] ? i : i_end;
+
+	      /* Move the changed region forward, so long as the
+		 first changed line matches the following unchanged one.
+		 This merges with following changed regions.
+		 Do this second, so that if there are no merges,
+		 the changed region is moved forward as far as possible.  */
+
+	      while (i != i_end && equivs[start] == equivs[i])
+		{
+		  changed[start++] = 0;
+		  changed[i++] = 1;
+		  while (changed[i])
+		    i++;
+		  while (other_changed[++j])
+		    corresponding = i;
+		}
+	    }
+	  while (runlength != i - start);
+
+	  /* If possible, move the fully-merged run of changes
+	     back to a corresponding run in the other file.  */
+
+	  while (corresponding < i)
+	    {
+	      changed[--start] = 1;
+	      changed[--i] = 0;
+	      while (other_changed[--j])
+		continue;
+	    }
+	}
+    }
+}
+
+/* Cons an additional entry onto the front of an edit script OLD.
+   LINE0 and LINE1 are the first affected lines in the two files (origin 0).
+   DELETED is the number of lines deleted here from file 0.
+   INSERTED is the number of lines inserted here in file 1.
+
+   If DELETED is 0 then LINE0 is the number of the line before
+   which the insertion was done; vice versa for INSERTED and LINE1.  */
+
+static struct change *
+add_change (line0, line1, deleted, inserted, old)
+     int line0, line1, deleted, inserted;
+     struct change *old;
+{
+  struct change *new = (struct change *) xmalloc (sizeof (struct change));
+
+  new->line0 = line0;
+  new->line1 = line1;
+  new->inserted = inserted;
+  new->deleted = deleted;
+  new->link = old;
+  return new;
+}
+
+/* Scan the tables of which lines are inserted and deleted,
+   producing an edit script in reverse order.  */
+
+static struct change *
+build_reverse_script (filevec)
+     struct file_data const filevec[];
+{
+  struct change *script = 0;
+  char *changed0 = filevec[0].changed_flag;
+  char *changed1 = filevec[1].changed_flag;
+  int len0 = filevec[0].buffered_lines;
+  int len1 = filevec[1].buffered_lines;
+
+  /* Note that changedN[len0] does exist, and contains 0.  */
+
+  int i0 = 0, i1 = 0;
+
+  while (i0 < len0 || i1 < len1)
+    {
+      if (changed0[i0] || changed1[i1])
+	{
+	  int line0 = i0, line1 = i1;
+
+	  /* Find # lines changed here in each file.  */
+	  while (changed0[i0]) ++i0;
+	  while (changed1[i1]) ++i1;
+
+	  /* Record this change.  */
+	  script = add_change (line0, line1, i0 - line0, i1 - line1, script);
+	}
+
+      /* We have reached lines in the two files that match each other.  */
+      i0++, i1++;
+    }
+
+  return script;
+}
+
+/* Scan the tables of which lines are inserted and deleted,
+   producing an edit script in forward order.  */
+
+static struct change *
+build_script (filevec)
+     struct file_data const filevec[];
+{
+  struct change *script = 0;
+  char *changed0 = filevec[0].changed_flag;
+  char *changed1 = filevec[1].changed_flag;
+  int i0 = filevec[0].buffered_lines, i1 = filevec[1].buffered_lines;
+
+  /* Note that changedN[-1] does exist, and contains 0.  */
+
+  while (i0 >= 0 || i1 >= 0)
+    {
+      if (changed0[i0 - 1] || changed1[i1 - 1])
+	{
+	  int line0 = i0, line1 = i1;
+
+	  /* Find # lines changed here in each file.  */
+	  while (changed0[i0 - 1]) --i0;
+	  while (changed1[i1 - 1]) --i1;
+
+	  /* Record this change.  */
+	  script = add_change (i0, i1, line0 - i0, line1 - i1, script);
+	}
+
+      /* We have reached lines in the two files that match each other.  */
+      i0--, i1--;
+    }
+
+  return script;
+}
+
+/* If CHANGES, briefly report that two files differed.  */
+static void
+briefly_report (changes, filevec)
+     int changes;
+     struct file_data const filevec[];
+{
+  if (changes)
+    message (no_details_flag ? "Files %s and %s differ\n"
+	     : "Binary files %s and %s differ\n",
+	     filevec[0].name, filevec[1].name);
+}
+
+/* Report the differences of two files.  DEPTH is the current directory
+   depth. */
+int
+diff_2_files (filevec, depth)
+     struct file_data filevec[];
+     int depth;
+{
+  int diags;
+  int i;
+  struct change *e, *p;
+  struct change *script;
+  int changes;
+
+
+  /* If we have detected that either file is binary,
+     compare the two files as binary.  This can happen
+     only when the first chunk is read.
+     Also, --brief without any --ignore-* options means
+     we can speed things up by treating the files as binary.  */
+
+  if (read_files (filevec, no_details_flag & ~ignore_some_changes))
+    {
+      /* Files with different lengths must be different.  */
+      if (filevec[0].stat.st_size != filevec[1].stat.st_size
+	  && (filevec[0].desc < 0 || S_ISREG (filevec[0].stat.st_mode))
+	  && (filevec[1].desc < 0 || S_ISREG (filevec[1].stat.st_mode)))
+	changes = 1;
+
+      /* Standard input equals itself.  */
+      else if (filevec[0].desc == filevec[1].desc)
+	changes = 0;
+
+      else
+	/* Scan both files, a buffer at a time, looking for a difference.  */
+	{
+	  /* Allocate same-sized buffers for both files.  */
+	  size_t buffer_size = buffer_lcm (STAT_BLOCKSIZE (filevec[0].stat),
+					   STAT_BLOCKSIZE (filevec[1].stat));
+	  for (i = 0; i < 2; i++)
+	    filevec[i].buffer = xrealloc (filevec[i].buffer, buffer_size);
+
+	  for (;;  filevec[0].buffered_chars = filevec[1].buffered_chars = 0)
+	    {
+	      /* Read a buffer's worth from both files.  */
+	      for (i = 0; i < 2; i++)
+		if (0 <= filevec[i].desc)
+		  while (filevec[i].buffered_chars != buffer_size)
+		    {
+		      int r = read (filevec[i].desc,
+				    filevec[i].buffer
+				    + filevec[i].buffered_chars,
+				    buffer_size - filevec[i].buffered_chars);
+		      if (r == 0)
+			break;
+		      if (r < 0)
+			pfatal_with_name (filevec[i].name);
+		      filevec[i].buffered_chars += r;
+		    }
+
+	      /* If the buffers differ, the files differ.  */
+	      if (filevec[0].buffered_chars != filevec[1].buffered_chars
+		  || (filevec[0].buffered_chars != 0
+		      && memcmp (filevec[0].buffer,
+				 filevec[1].buffer,
+				 filevec[0].buffered_chars) != 0))
+		{
+		  changes = 1;
+		  break;
+		}
+
+	      /* If we reach end of file, the files are the same.  */
+	      if (filevec[0].buffered_chars != buffer_size)
+		{
+		  changes = 0;
+		  break;
+		}
+	    }
+	}
+
+      briefly_report (changes, filevec);
+    }
+  else
+    {
+      /* Allocate vectors for the results of comparison:
+	 a flag for each line of each file, saying whether that line
+	 is an insertion or deletion.
+	 Allocate an extra element, always zero, at each end of each vector.  */
+
+      size_t s = filevec[0].buffered_lines + filevec[1].buffered_lines + 4;
+      filevec[0].changed_flag = xmalloc (s);
+      bzero (filevec[0].changed_flag, s);
+      filevec[0].changed_flag++;
+      filevec[1].changed_flag = filevec[0].changed_flag
+				+ filevec[0].buffered_lines + 2;
+
+      /* Some lines are obviously insertions or deletions
+	 because they don't match anything.  Detect them now, and
+	 avoid even thinking about them in the main comparison algorithm.  */
+
+      discard_confusing_lines (filevec);
+
+      /* Now do the main comparison algorithm, considering just the
+	 undiscarded lines.  */
+
+      xvec = filevec[0].undiscarded;
+      yvec = filevec[1].undiscarded;
+      diags = filevec[0].nondiscarded_lines + filevec[1].nondiscarded_lines + 3;
+      fdiag = (int *) xmalloc (diags * (2 * sizeof (int)));
+      bdiag = fdiag + diags;
+      fdiag += filevec[1].nondiscarded_lines + 1;
+      bdiag += filevec[1].nondiscarded_lines + 1;
+
+      /* Set TOO_EXPENSIVE to be approximate square root of input size,
+	 bounded below by 256.  */
+      too_expensive = 1;
+      for (i = filevec[0].nondiscarded_lines + filevec[1].nondiscarded_lines;
+	   i != 0; i >>= 2)
+	too_expensive <<= 1;
+      too_expensive = max (256, too_expensive);
+
+      files[0] = filevec[0];
+      files[1] = filevec[1];
+
+      compareseq (0, filevec[0].nondiscarded_lines,
+		  0, filevec[1].nondiscarded_lines, no_discards);
+
+      free (fdiag - (filevec[1].nondiscarded_lines + 1));
+
+      /* Modify the results slightly to make them prettier
+	 in cases where that can validly be done.  */
+
+      shift_boundaries (filevec);
+
+      /* Get the results of comparison in the form of a chain
+	 of `struct change's -- an edit script.  */
+
+      if (output_style == OUTPUT_ED)
+	script = build_reverse_script (filevec);
+      else
+	script = build_script (filevec);
+
+      /* Set CHANGES if we had any diffs.
+	 If some changes are ignored, we must scan the script to decide.  */
+      if (ignore_blank_lines_flag || ignore_regexp_list)
+	{
+	  struct change *next = script;
+	  changes = 0;
+
+	  while (next && changes == 0)
+	    {
+	      struct change *this, *end;
+	      int first0, last0, first1, last1, deletes, inserts;
+
+	      /* Find a set of changes that belong together.  */
+	      this = next;
+	      end = find_change (next);
+
+	      /* Disconnect them from the rest of the changes, making them
+		 a hunk, and remember the rest for next iteration.  */
+	      next = end->link;
+	      end->link = 0;
+
+	      /* Determine whether this hunk is really a difference.  */
+	      analyze_hunk (this, &first0, &last0, &first1, &last1,
+			    &deletes, &inserts);
+
+	      /* Reconnect the script so it will all be freed properly.  */
+	      end->link = next;
+
+	      if (deletes || inserts)
+		changes = 1;
+	    }
+	}
+      else
+	changes = (script != 0);
+
+      if (no_details_flag)
+	briefly_report (changes, filevec);
+      else
+	{
+	  if (changes || ! no_diff_means_no_output)
+	    {
+	      /* Record info for starting up output,
+		 to be used if and when we have some output to print.  */
+	      setup_output (files[0].name, files[1].name, depth);
+
+	      switch (output_style)
+		{
+		case OUTPUT_CONTEXT:
+		  print_context_script (script, 0);
+		  break;
+
+		case OUTPUT_UNIFIED:
+		  print_context_script (script, 1);
+		  break;
+
+		case OUTPUT_ED:
+		  print_ed_script (script);
+		  break;
+
+		case OUTPUT_FORWARD_ED:
+		  pr_forward_ed_script (script);
+		  break;
+
+		case OUTPUT_RCS:
+		  print_rcs_script (script);
+		  break;
+
+		case OUTPUT_NORMAL:
+		  print_normal_script (script);
+		  break;
+
+		case OUTPUT_IFDEF:
+		  print_ifdef_script (script);
+		  break;
+
+		case OUTPUT_SDIFF:
+		  print_sdiff_script (script);
+		}
+
+	      finish_output ();
+	    }
+	}
+
+      free (filevec[0].undiscarded);
+
+      free (filevec[0].changed_flag - 1);
+
+      for (i = 1; i >= 0; --i)
+	free (filevec[i].equivs);
+
+      for (i = 0; i < 2; ++i)
+	free (filevec[i].linbuf + filevec[i].linbuf_base);
+
+      for (e = script; e; e = p)
+	{
+	  p = e->link;
+	  free (e);
+	}
+
+      if (! ROBUST_OUTPUT_STYLE (output_style))
+	for (i = 0; i < 2; ++i)
+	  if (filevec[i].missing_newline)
+	    {
+	      error ("No newline at end of file %s", filevec[i].name, "");
+	      changes = 2;
+	    }
+    }
+
+  if (filevec[0].buffer != filevec[1].buffer)
+    free (filevec[0].buffer);
+  free (filevec[1].buffer);
+
+  return changes;
+}
diff --git a/gnu/usr.bin/diff/cmpbuf.c b/gnu/usr.bin/diff/cmpbuf.c
new file mode 100644
index 00000000000..e95a8f98ed9
--- /dev/null
+++ b/gnu/usr.bin/diff/cmpbuf.c
@@ -0,0 +1,40 @@
+/* Buffer primitives for comparison operations.
+   Copyright (C) 1993 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "system.h"
+#include "cmpbuf.h"
+
+/* Least common multiple of two buffer sizes A and B.  */
+
+size_t
+buffer_lcm (a, b)
+     size_t a, b;
+{
+  size_t m, n, r;
+
+  /* Yield reasonable values if buffer sizes are zero.  */
+  if (!a)
+    return b ? b : 8 * 1024;
+  if (!b)
+    return a;
+
+  /* n = gcd (a, b) */
+  for (m = a, n = b;  (r = m % n) != 0;  m = n, n = r)
+    continue;
+
+  return a/n * b;
+}
diff --git a/gnu/usr.bin/diff/cmpbuf.h b/gnu/usr.bin/diff/cmpbuf.h
new file mode 100644
index 00000000000..e3852b7bd4f
--- /dev/null
+++ b/gnu/usr.bin/diff/cmpbuf.h
@@ -0,0 +1,20 @@
+/* Buffer primitives for comparison operations.
+   Copyright (C) 1993 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+size_t buffer_lcm PARAMS((size_t, size_t));
diff --git a/gnu/usr.bin/diff/config.h b/gnu/usr.bin/diff/config.h
new file mode 100644
index 00000000000..3d7e65b7b41
--- /dev/null
+++ b/gnu/usr.bin/diff/config.h
@@ -0,0 +1,118 @@
+/* config.h.  Generated automatically by configure.  */
+/* config.hin.  Generated automatically from configure.in by autoheader.  */
+
+/* Define if using alloca.c.  */
+/* #undef C_ALLOCA */
+
+/* Define if the closedir function returns void instead of int.  */
+/* #undef CLOSEDIR_VOID */
+
+/* Define to empty if the keyword does not work.  */
+/* #undef const */
+
+/* Define to one of _getb67, GETB67, getb67 for Cray-2 and Cray-YMP systems.
+   This function is required for alloca.c support on those systems.  */
+/* #undef CRAY_STACKSEG_END */
+
+/* Define if you have <alloca.h> and it should be used (not on Ultrix).  */
+/* #undef HAVE_ALLOCA_H */
+
+/* Define if you don't have vprintf but do have _doprnt.  */
+/* #undef HAVE_DOPRNT */
+
+/* Define if your struct stat has st_blksize.  */
+#define HAVE_ST_BLKSIZE 1
+
+/* Define if you have <vfork.h>.  */
+/* #undef HAVE_VFORK_H */
+
+/* Define if you have the vprintf function.  */
+#define HAVE_VPRINTF 1
+
+/* Define if on MINIX.  */
+/* #undef _MINIX */
+
+/* Define to `int' if <sys/types.h> doesn't define.  */
+/* #undef pid_t */
+
+/* Define if the system does not provide POSIX.1 features except
+   with this defined.  */
+/* #undef _POSIX_1_SOURCE */
+
+/* Define if you need to in order for stat and other things to work.  */
+/* #undef _POSIX_SOURCE */
+
+/* Define as the return type of signal handlers (int or void).  */
+#define RETSIGTYPE void
+
+/* If using the C implementation of alloca, define if you know the
+   direction of stack growth for your system; otherwise it will be
+   automatically deduced at run-time.
+	STACK_DIRECTION > 0 => grows toward higher addresses
+	STACK_DIRECTION < 0 => grows toward lower addresses
+	STACK_DIRECTION = 0 => direction of growth unknown
+ */
+/* #undef STACK_DIRECTION */
+
+/* Define if the `S_IS*' macros in <sys/stat.h> do not work properly.  */
+/* #undef STAT_MACROS_BROKEN */
+
+/* Define if you have the ANSI C header files.  */
+#define STDC_HEADERS 1
+
+/* Define if <sys/wait.h> is compatible with Posix applications.  */
+#define HAVE_SYS_WAIT_H 1
+
+/* Define vfork as fork if vfork does not work.  */
+/* #undef vfork */
+
+/* Define if you have the dup2 function.  */
+#define HAVE_DUP2 1
+
+/* Define if you have the memchr function.  */
+#define HAVE_MEMCHR 1
+
+/* Define if you have the sigaction function.  */
+#define HAVE_SIGACTION 1
+
+/* Define if you have the strchr function.  */
+#define HAVE_STRCHR 1
+
+/* Define if you have the strerror function.  */
+#define HAVE_STRERROR 1
+
+/* Define if you have the tmpnam function.  */
+#define HAVE_TMPNAM 1
+
+/* Define if you have the <dirent.h> header file.  */
+#define HAVE_DIRENT_H 1
+
+/* Define if you have the <fcntl.h> header file.  */
+#define HAVE_FCNTL_H 1
+
+/* Define if you have the <limits.h> header file.  */
+#define HAVE_LIMITS_H 1
+
+/* Define if you have the <ndir.h> header file.  */
+/* #undef HAVE_NDIR_H */
+
+/* Define if you have the <stdlib.h> header file.  */
+#define HAVE_STDLIB_H 1
+
+/* Define if you have the <string.h> header file.  */
+#define HAVE_STRING_H 1
+
+/* Define if you have the <sys/dir.h> header file.  */
+/* #undef HAVE_SYS_DIR_H */
+
+/* Define if you have the <sys/file.h> header file.  */
+#define HAVE_SYS_FILE_H 1
+
+/* Define if you have the <sys/ndir.h> header file.  */
+/* #undef HAVE_SYS_NDIR_H */
+
+/* Define if you have the <time.h> header file.  */
+#define HAVE_TIME_H 1
+
+/* Define if you have the <unistd.h> header file.  */
+#define HAVE_UNISTD_H 1
diff --git a/gnu/usr.bin/diff/context.c b/gnu/usr.bin/diff/context.c
new file mode 100644
index 00000000000..14f950c5269
--- /dev/null
+++ b/gnu/usr.bin/diff/context.c
@@ -0,0 +1,468 @@
+/* Context-format output routines for GNU DIFF.
+   Copyright (C) 1988,1989,1991,1992,1993,1994 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "diff.h"
+
+static struct change *find_hunk PARAMS((struct change *));
+static void find_function PARAMS((struct file_data const *, int, char const **, size_t *));
+static void mark_ignorable PARAMS((struct change *));
+static void pr_context_hunk PARAMS((struct change *));
+static void pr_unidiff_hunk PARAMS((struct change *));
+static void print_context_label PARAMS ((char const *, struct file_data *, char const *));
+static void print_context_number_range PARAMS((struct file_data const *, int, int));
+static void print_unidiff_number_range PARAMS((struct file_data const *, int, int));
+
+/* Last place find_function started searching from.  */
+static int find_function_last_search;
+
+/* The value find_function returned when it started searching there.  */
+static int find_function_last_match;
+
+/* Print a label for a context diff, with a file name and date or a label.  */
+
+static void
+print_context_label (mark, inf, label)
+     char const *mark;
+     struct file_data *inf;
+     char const *label;
+{
+  if (label)
+    fprintf (outfile, "%s %s\n", mark, label);
+  else
+    {
+      char const *ct = ctime (&inf->stat.st_mtime);
+      if (!ct)
+	ct = "?\n";
+      /* See Posix.2 section 4.17.6.1.4 for this format.  */
+      fprintf (outfile, "%s %s\t%s", mark, inf->name, ct);
+    }
+}
+
+/* Print a header for a context diff, with the file names and dates.  */
+
+void
+print_context_header (inf, unidiff_flag)
+     struct file_data inf[];
+     int unidiff_flag;
+{
+  if (unidiff_flag)
+    {
+      print_context_label ("---", &inf[0], file_label[0]);
+      print_context_label ("+++", &inf[1], file_label[1]);
+    }
+  else
+    {
+      print_context_label ("***", &inf[0], file_label[0]);
+      print_context_label ("---", &inf[1], file_label[1]);
+    }
+}
+
+/* Print an edit script in context format.  */
+
+void
+print_context_script (script, unidiff_flag)
+     struct change *script;
+     int unidiff_flag;
+{
+  if (ignore_blank_lines_flag || ignore_regexp_list)
+    mark_ignorable (script);
+  else
+    {
+      struct change *e;
+      for (e = script; e; e = e->link)
+	e->ignore = 0;
+    }
+
+  find_function_last_search = - files[0].prefix_lines;
+  find_function_last_match = find_function_last_search - 1;
+
+  if (unidiff_flag)
+    print_script (script, find_hunk, pr_unidiff_hunk);
+  else
+    print_script (script, find_hunk, pr_context_hunk);
+}
+
+/* Print a pair of line numbers with a comma, translated for file FILE.
+   If the second number is not greater, use the first in place of it.
+
+   Args A and B are internal line numbers.
+   We print the translated (real) line numbers.  */
+
+static void
+print_context_number_range (file, a, b)
+     struct file_data const *file;
+     int a, b;
+{
+  int trans_a, trans_b;
+  translate_range (file, a, b, &trans_a, &trans_b);
+
+  /* Note: we can have B < A in the case of a range of no lines.
+     In this case, we should print the line number before the range,
+     which is B.  */
+  if (trans_b > trans_a)
+    fprintf (outfile, "%d,%d", trans_a, trans_b);
+  else
+    fprintf (outfile, "%d", trans_b);
+}
+
+/* Print a portion of an edit script in context format.
+   HUNK is the beginning of the portion to be printed.
+   The end is marked by a `link' that has been nulled out.
+
+   Prints out lines from both files, and precedes each
+   line with the appropriate flag-character.  */
+
+static void
+pr_context_hunk (hunk)
+     struct change *hunk;
+{
+  int first0, last0, first1, last1, show_from, show_to, i;
+  struct change *next;
+  char const *prefix;
+  char const *function;
+  size_t function_length;
+  FILE *out;
+
+  /* Determine range of line numbers involved in each file.  */
+
+  analyze_hunk (hunk, &first0, &last0, &first1, &last1, &show_from, &show_to);
+
+  if (!show_from && !show_to)
+    return;
+
+  /* Include a context's width before and after.  */
+
+  i = - files[0].prefix_lines;
+  first0 = max (first0 - context, i);
+  first1 = max (first1 - context, i);
+  last0 = min (last0 + context, files[0].valid_lines - 1);
+  last1 = min (last1 + context, files[1].valid_lines - 1);
+
+  /* If desired, find the preceding function definition line in file 0.  */
+  function = 0;
+  if (function_regexp_list)
+    find_function (&files[0], first0, &function, &function_length);
+
+  begin_output ();
+  out = outfile;
+
+  /* If we looked for and found a function this is part of,
+     include its name in the header of the diff section.  */
+  fprintf (out, "***************");
+
+  if (function)
+    {
+      fprintf (out, " ");
+      fwrite (function, 1, min (function_length - 1, 40), out);
+    }
+
+  fprintf (out, "\n*** ");
+  print_context_number_range (&files[0], first0, last0);
+  fprintf (out, " ****\n");
+
+  if (show_from)
+    {
+      next = hunk;
+
+      for (i = first0; i <= last0; i++)
+	{
+	  /* Skip past changes that apply (in file 0)
+	     only to lines before line I.  */
+
+	  while (next && next->line0 + next->deleted <= i)
+	    next = next->link;
+
+	  /* Compute the marking for line I.  */
+
+	  prefix = " ";
+	  if (next && next->line0 <= i)
+	    /* The change NEXT covers this line.
+	       If lines were inserted here in file 1, this is "changed".
+	       Otherwise it is "deleted".  */
+	    prefix = (next->inserted > 0 ? "!" : "-");
+
+	  print_1_line (prefix, &files[0].linbuf[i]);
+	}
+    }
+
+  fprintf (out, "--- ");
+  print_context_number_range (&files[1], first1, last1);
+  fprintf (out, " ----\n");
+
+  if (show_to)
+    {
+      next = hunk;
+
+      for (i = first1; i <= last1; i++)
+	{
+	  /* Skip past changes that apply (in file 1)
+	     only to lines before line I.  */
+
+	  while (next && next->line1 + next->inserted <= i)
+	    next = next->link;
+
+	  /* Compute the marking for line I.  */
+
+	  prefix = " ";
+	  if (next && next->line1 <= i)
+	    /* The change NEXT covers this line.
+	       If lines were deleted here in file 0, this is "changed".
+	       Otherwise it is "inserted".  */
+	    prefix = (next->deleted > 0 ? "!" : "+");
+
+	  print_1_line (prefix, &files[1].linbuf[i]);
+	}
+    }
+}
+
+/* Print a pair of line numbers with a comma, translated for file FILE.
+   If the second number is smaller, use the first in place of it.
+   If the numbers are equal, print just one number.
+
+   Args A and B are internal line numbers.
+   We print the translated (real) line numbers.  */
+
+static void
+print_unidiff_number_range (file, a, b)
+     struct file_data const *file;
+     int a, b;
+{
+  int trans_a, trans_b;
+  translate_range (file, a, b, &trans_a, &trans_b);
+
+  /* Note: we can have B < A in the case of a range of no lines.
+     In this case, we should print the line number before the range,
+     which is B.  */
+  if (trans_b <= trans_a)
+    fprintf (outfile, trans_b == trans_a ? "%d" : "%d,0", trans_b);
+  else
+    fprintf (outfile, "%d,%d", trans_a, trans_b - trans_a + 1);
+}
+
+/* Print a portion of an edit script in unidiff format.
+   HUNK is the beginning of the portion to be printed.
+   The end is marked by a `link' that has been nulled out.
+
+   Prints out lines from both files, and precedes each
+   line with the appropriate flag-character.  */
+
+static void
+pr_unidiff_hunk (hunk)
+     struct change *hunk;
+{
+  int first0, last0, first1, last1, show_from, show_to, i, j, k;
+  struct change *next;
+  char const *function;
+  size_t function_length;
+  FILE *out;
+
+  /* Determine range of line numbers involved in each file.  */
+
+  analyze_hunk (hunk, &first0, &last0, &first1, &last1, &show_from, &show_to);
+
+  if (!show_from && !show_to)
+    return;
+
+  /* Include a context's width before and after.  */
+
+  i = - files[0].prefix_lines;
+  first0 = max (first0 - context, i);
+  first1 = max (first1 - context, i);
+  last0 = min (last0 + context, files[0].valid_lines - 1);
+  last1 = min (last1 + context, files[1].valid_lines - 1);
+
+  /* If desired, find the preceding function definition line in file 0.  */
+  function = 0;
+  if (function_regexp_list)
+    find_function (&files[0], first0, &function, &function_length);
+
+  begin_output ();
+  out = outfile;
+
+  fprintf (out, "@@ -");
+  print_unidiff_number_range (&files[0], first0, last0);
+  fprintf (out, " +");
+  print_unidiff_number_range (&files[1], first1, last1);
+  fprintf (out, " @@");
+
+  /* If we looked for and found a function this is part of,
+     include its name in the header of the diff section.  */
+
+  if (function)
+    {
+      putc (' ', out);
+      fwrite (function, 1, min (function_length - 1, 40), out);
+    }
+  putc ('\n', out);
+
+  next = hunk;
+  i = first0;
+  j = first1;
+
+  while (i <= last0 || j <= last1)
+    {
+
+      /* If the line isn't a difference, output the context from file 0. */
+
+      if (!next || i < next->line0)
+	{
+	  putc (tab_align_flag ? '\t' : ' ', out);
+	  print_1_line (0, &files[0].linbuf[i++]);
+	  j++;
+	}
+      else
+	{
+	  /* For each difference, first output the deleted part. */
+
+	  k = next->deleted;
+	  while (k--)
+	    {
+	      putc ('-', out);
+	      if (tab_align_flag)
+		putc ('\t', out);
+	      print_1_line (0, &files[0].linbuf[i++]);
+	    }
+
+	  /* Then output the inserted part. */
+
+	  k = next->inserted;
+	  while (k--)
+	    {
+	      putc ('+', out);
+	      if (tab_align_flag)
+		putc ('\t', out);
+	      print_1_line (0, &files[1].linbuf[j++]);
+	    }
+
+	  /* We're done with this hunk, so on to the next! */
+
+	  next = next->link;
+	}
+    }
+}
+
+/* Scan a (forward-ordered) edit script for the first place that more than
+   2*CONTEXT unchanged lines appear, and return a pointer
+   to the `struct change' for the last change before those lines.  */
+
+static struct change *
+find_hunk (start)
+     struct change *start;
+{
+  struct change *prev;
+  int top0, top1;
+  int thresh;
+
+  do
+    {
+      /* Compute number of first line in each file beyond this changed.  */
+      top0 = start->line0 + start->deleted;
+      top1 = start->line1 + start->inserted;
+      prev = start;
+      start = start->link;
+      /* Threshold distance is 2*CONTEXT between two non-ignorable changes,
+	 but only CONTEXT if one is ignorable.  */
+      thresh = ((prev->ignore || (start && start->ignore))
+		? context
+		: 2 * context + 1);
+      /* It is not supposed to matter which file we check in the end-test.
+	 If it would matter, crash.  */
+      if (start && start->line0 - top0 != start->line1 - top1)
+	abort ();
+    } while (start
+	     /* Keep going if less than THRESH lines
+		elapse before the affected line.  */
+	     && start->line0 < top0 + thresh);
+
+  return prev;
+}
+
+/* Set the `ignore' flag properly in each change in SCRIPT.
+   It should be 1 if all the lines inserted or deleted in that change
+   are ignorable lines.  */
+
+static void
+mark_ignorable (script)
+     struct change *script;
+{
+  while (script)
+    {
+      struct change *next = script->link;
+      int first0, last0, first1, last1, deletes, inserts;
+
+      /* Turn this change into a hunk: detach it from the others.  */
+      script->link = 0;
+
+      /* Determine whether this change is ignorable.  */
+      analyze_hunk (script, &first0, &last0, &first1, &last1, &deletes, &inserts);
+      /* Reconnect the chain as before.  */
+      script->link = next;
+
+      /* If the change is ignorable, mark it.  */
+      script->ignore = (!deletes && !inserts);
+
+      /* Advance to the following change.  */
+      script = next;
+    }
+}
+
+/* Find the last function-header line in FILE prior to line number LINENUM.
+   This is a line containing a match for the regexp in `function_regexp'.
+   Store the address of the line text into LINEP and the length of the
+   line into LENP.
+   Do not store anything if no function-header is found.  */
+
+static void
+find_function (file, linenum, linep, lenp)
+     struct file_data const *file;
+     int linenum;
+     char const **linep;
+     size_t *lenp;
+{
+  int i = linenum;
+  int last = find_function_last_search;
+  find_function_last_search = i;
+
+  while (--i >= last)
+    {
+      /* See if this line is what we want.  */
+      struct regexp_list *r;
+      char const *line = file->linbuf[i];
+      size_t len = file->linbuf[i + 1] - line;
+
+      for (r = function_regexp_list; r; r = r->next)
+	if (0 <= re_search (&r->buf, line, len, 0, len, 0))
+	  {
+	    *linep = line;
+	    *lenp = len;
+	    find_function_last_match = i;
+	    return;
+	  }
+    }
+  /* If we search back to where we started searching the previous time,
+     find the line we found last time.  */
+  if (find_function_last_match >= - file->prefix_lines)
+    {
+      i = find_function_last_match;
+      *linep = file->linbuf[i];
+      *lenp = file->linbuf[i + 1] - *linep;
+      return;
+    }
+  return;
+}
diff --git a/gnu/usr.bin/diff/diff.1 b/gnu/usr.bin/diff/diff.1
new file mode 100644
index 00000000000..e16f6d98dcf
--- /dev/null
+++ b/gnu/usr.bin/diff/diff.1
@@ -0,0 +1,473 @@
+.TH DIFF 1 "22sep1993" "GNU Tools" "GNU Tools"
+.SH NAME
+diff \- find differences between two files
+.SH SYNOPSIS
+.B diff
+[options] from-file to-file
+.SH DESCRIPTION
+In the simplest case, 
+.I diff
+compares the contents of the two files
+.I from-file
+and
+.IR to-file .
+A file name of
+.B \-
+stands for
+text read from the standard input.  As a special case,
+.B "diff \- \-"
+compares a copy of standard input to itself.
+
+If 
+.I from-file
+is a directory and
+.I to-file
+is not,
+.I diff
+compares the file in
+.I from-file
+whose file name is that of
+.IR to-file ,
+and vice versa.  The non-directory file must not be
+.BR \- .
+
+If both
+.I from-file
+and
+.I to-file
+are directories,
+.I diff
+compares corresponding files in both directories, in
+alphabetical order; this comparison is not recursive unless the
+.B \-r
+or
+.B \-\-recursive
+option is given.
+.I diff
+never
+compares the actual contents of a directory as if it were a file.  The
+file that is fully specified may not be standard input, because standard
+input is nameless and the notion of ``file with the same name'' does not
+apply.
+
+.B diff
+options begin with
+.BR \- ,
+so normally
+.I from-file
+and
+.I to-file
+may not begin with
+.BR \- .
+However,
+.B \-\-
+as an
+argument by itself treats the remaining arguments as file names even if
+they begin with
+.BR \- .
+.SS Options
+Below is a summary of all of the options that GNU
+.I diff
+accepts.
+Most options have two equivalent names, one of which is a single letter
+preceded by
+.BR \- ,
+and the other of which is a long name preceded by
+.BR \-\- .
+Multiple single letter options (unless they take an
+argument) can be combined into a single command line word:
+.B \-ac
+is
+equivalent to
+.BR "\-a \-c" .
+Long named options can be abbreviated to
+any unique prefix of their name.  Brackets
+.RB ( [
+and
+.BR ] )
+indicate that an
+option takes an optional argument.
+.TP
+.BI \- lines
+Show
+.I lines
+(an integer) lines of context.  This option does not
+specify an output format by itself; it has no effect unless it is
+combined with
+.B \-c
+or
+.BR \-u .
+This option is obsolete.  For proper
+operation,
+.I patch
+typically needs at least two lines of context.
+.TP
+.B \-a
+Treat all files as text and compare them line-by-line, even if they
+do not seem to be text.
+.TP
+.B \-b
+Ignore changes in amount of white space.
+.TP
+.B \-B
+Ignore changes that just insert or delete blank lines.
+.TP
+.B \-\-brief
+Report only whether the files differ, not the details of the
+differences.
+.TP
+.B \-c
+Use the context output format.
+.TP
+.BI "\-C " lines
+.br
+.ns
+.TP
+.BI \-\-context[= lines ]
+Use the context output format, showing
+.I lines
+(an integer) lines of
+context, or three if
+.I lines
+is not given.
+For proper operation,
+.I patch
+typically needs at least two lines of
+context.
+.TP
+.BI \-\-changed\-group\-format= format
+Use
+.I format
+to output a line group containing differing lines from
+both files in if-then-else format.
+.TP
+.B \-d
+Change the algorithm to perhaps find a smaller set of changes.  This makes
+.I diff
+slower (sometimes much slower).
+.TP
+.BI "\-D " name
+Make merged if-then-else format output, conditional on the preprocessor
+macro
+.IR name .
+.TP
+.B \-e
+.br
+.ns
+.TP
+.B \-\-ed
+Make output that is a valid
+.I ed
+script.
+.TP
+.BI \-\-exclude= pattern
+When comparing directories, ignore files and subdirectories whose basenames
+match
+.IR pattern .
+.TP
+.BI \-\-exclude\-from= file
+When comparing directories, ignore files and subdirectories whose basenames
+match any pattern contained in
+.IR file .
+.TP
+.B \-\-expand\-tabs
+Expand tabs to spaces in the output, to preserve the alignment of tabs
+in the input files.
+.TP
+.B \-f
+Make output that looks vaguely like an
+.I ed
+script but has changes
+in the order they appear in the file.
+.TP
+.BI "\-F " regexp
+In context and unified format, for each hunk of differences, show some
+of the last preceding line that matches
+.IR regexp .
+.TP
+.B \-\-forward\-ed
+Make output that looks vaguely like an
+.B ed
+script but has changes
+in the order they appear in the file.
+.TP
+.B \-h
+This option currently has no effect; it is present for Unix
+compatibility.
+.TP
+.B \-H
+Use heuristics to speed handling of large files that have numerous
+scattered small changes.
+.TP
+.BI \-\-horizon\-lines= lines
+Do not discard the last
+.I lines
+lines of the common prefix
+and the first
+.I lines
+lines of the common suffix.
+.TP
+.B \-i
+Ignore changes in case; consider upper- and lower-case letters
+equivalent.
+.TP
+.BI "\-I " regexp
+Ignore changes that just insert or delete lines that match
+.IR regexp .
+.TP
+.BI \-\-ifdef= name
+Make merged if-then-else format output, conditional on the preprocessor
+macro
+.IR name .
+.TP
+.B \-\-ignore\-all\-space
+Ignore white space when comparing lines.
+.TP
+.B \-\-ignore\-blank\-lines
+Ignore changes that just insert or delete blank lines.
+.TP
+.B \-\-ignore\-case
+Ignore changes in case; consider upper- and lower-case to be the same.
+.TP
+.BI \-\-ignore\-matching\-lines= regexp
+Ignore changes that just insert or delete lines that match
+.IR regexp .
+.TP
+.B \-\-ignore\-space\-change
+Ignore changes in amount of white space.
+.TP
+.B \-\-initial\-tab
+Output a tab rather than a space before the text of a line in normal or
+context format.  This causes the alignment of tabs in the line to look
+normal.
+.TP
+.B \-l
+Pass the output through
+.I pr
+to paginate it.
+.TP
+.BI "\-L " label
+.br
+.ns
+.TP
+.BI \-\-label= label
+Use
+.I label
+instead of the file name in the context format
+and unified format
+headers.
+.TP
+.B \-\-left\-column
+Print only the left column of two common lines in side by side format.
+.TP
+.BI \-\-line\-format= format
+Use
+.I format
+to output all input lines in in-then-else format.
+.TP
+.B \-\-minimal
+Change the algorithm to perhaps find a smaller set of changes.  This
+makes
+.I diff
+slower (sometimes much slower).
+.TP
+.B \-n
+Output RCS-format diffs; like
+.B \-f
+except that each command
+specifies the number of lines affected.
+.TP
+.B \-N
+.br
+.ns
+.TP
+.B \-\-new\-file
+In directory comparison, if a file is found in only one directory,
+treat it as present but empty in the other directory.
+.TP
+.BI \-\-new\-group\-format= format
+Use
+.I format
+to output a group of lines taken from just the second
+file in if-then-else format.
+.TP
+.BI \-\-new\-line\-format= format
+Use 
+.I format
+to output a line taken from just the second file in
+if-then-else format.
+.TP
+.BI \-\-old\-group\-format= format
+Use
+.I format
+to output a group of lines taken from just the first
+file in if-then-else format.
+.TP
+.BI \-\-old\-line\-format= format
+Use
+.I format
+to output a line taken from just the first file in
+if-then-else format.
+.TP
+.B \-p
+Show which C function each change is in.
+.TP
+.B \-P
+When comparing directories, if a file appears only in the second
+directory of the two, treat it as present but empty in the other.
+.TP
+.B \-\-paginate
+Pass the output through
+.I pr
+to paginate it.
+.TP
+.B \-q
+Report only whether the files differ, not the details of the
+differences.
+.TP
+.B \-r
+When comparing directories, recursively compare any subdirectories
+found.
+.TP
+.B \-\-rcs
+Output RCS-format diffs; like
+.B \-f
+except that each command
+specifies the number of lines affected.
+.TP
+.B \-\-recursive
+When comparing directories, recursively compare any subdirectories
+found.
+.TP
+.B \-\-report\-identical\-files
+.br
+.ns
+.TP
+.B \-s
+Report when two files are the same.
+.TP
+.BI "\-S " file
+When comparing directories, start with the file
+.IR file .
+This is
+used for resuming an aborted comparison.
+.TP
+.B \-\-sdiff\-merge\-assist
+Print extra information to help
+.IR sdiff .
+.I sdiff
+uses this
+option when it runs
+.IR diff .
+This option is not intended for users
+to use directly.
+.TP
+.B \-\-show\-c\-function
+Show which C function each change is in.
+.TP
+.BI \-\-show\-function\-line= regexp
+In context and unified format, for each hunk of differences, show some
+of the last preceding line that matches
+.IR regexp .
+.TP
+.B \-\-side\-by\-side
+Use the side by side output format.
+.TP
+.B \-\-speed\-large\-files
+Use heuristics to speed handling of large files that have numerous
+scattered small changes.
+.TP
+.BI \-\-starting\-file= file
+When comparing directories, start with the file
+.IR file .
+This is
+used for resuming an aborted comparison.
+.TP
+.B \-\-suppress\-common\-lines
+Do not print common lines in side by side format.
+.TP
+.B \-t
+Expand tabs to spaces in the output, to preserve the alignment of tabs
+in the input files.
+.TP
+.B \-T
+Output a tab rather than a space before the text of a line in normal or
+context format.  This causes the alignment of tabs in the line to look
+normal.
+.TP
+.B \-\-text
+Treat all files as text and compare them line-by-line, even if they
+do not appear to be text.
+.TP
+.B \-u
+Use the unified output format.
+.TP
+.BI \-\-unchanged\-group\-format= format
+Use
+.I format
+to output a group of common lines taken from both files
+in if-then-else format.
+.TP
+.BI \-\-unchanged\-line\-format= format
+Use
+.I format
+to output a line common to both files in if-then-else
+format.
+.TP
+.B \-\-unidirectional\-new\-file
+When comparing directories, if a file appears only in the second
+directory of the two, treat it as present but empty in the other.
+.TP
+.BI "\-U " lines
+.br
+.ns
+.TP
+.BI \-\-unified[= lines ]
+Use the unified output format, showing
+.I lines
+(an integer) lines of
+context, or three if
+.I lines
+is not given.
+For proper operation,
+.I patch
+typically needs at least two lines of
+context.
+.TP
+.B \-v
+.br
+.ns
+.TP
+.B \-\-version
+Output the version number of
+.IR diff .
+.TP
+.B \-w
+Ignore white space when comparing lines.
+.TP
+.BI "\-W " columns
+.br
+.ns
+.TP
+.BI \-\-width= columns
+Use an output width of
+.I columns
+in side by side format.
+.TP
+.BI "\-x " pattern
+When comparing directories, ignore files and subdirectories whose basenames
+match
+.IR pattern .
+.TP
+.BI "\-X " file
+When comparing directories, ignore files and subdirectories whose basenames
+match any pattern contained in
+.IR file .
+.TP
+.B \-y
+Use the side by side output format.
+.SH SEE ALSO
+cmp(1), comm(1), diff3(1), ed(1), patch(1), pr(1), sdiff(1).
+.SH DIAGNOSTICS
+An exit status of 0 means no differences were found, 1 means some
+differences were found, and 2 means trouble.
diff --git a/gnu/usr.bin/diff/diff.c b/gnu/usr.bin/diff/diff.c
new file mode 100644
index 00000000000..ab1549be864
--- /dev/null
+++ b/gnu/usr.bin/diff/diff.c
@@ -0,0 +1,1106 @@
+/* GNU DIFF main routine.
+   Copyright (C) 1988, 1989, 1992, 1993, 1994 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* GNU DIFF was written by Mike Haertel, David Hayes,
+   Richard Stallman, Len Tower, and Paul Eggert.  */
+
+#define GDIFF_MAIN
+#include "diff.h"
+#include <signal.h>
+#include "getopt.h"
+#include "fnmatch.h"
+
+#ifndef DEFAULT_WIDTH
+#define DEFAULT_WIDTH 130
+#endif
+
+#ifndef GUTTER_WIDTH_MINIMUM
+#define GUTTER_WIDTH_MINIMUM 3
+#endif
+
+static char const *filetype PARAMS((struct stat const *));
+static char *option_list PARAMS((char **, int));
+static int add_exclude_file PARAMS((char const *));
+static int ck_atoi PARAMS((char const *, int *));
+static int compare_files PARAMS((char const *, char const *, char const *, char const *, int));
+static int specify_format PARAMS((char **, char *));
+static void add_exclude PARAMS((char const *));
+static void add_regexp PARAMS((struct regexp_list **, char const *));
+static void specify_style PARAMS((enum output_style));
+static void try_help PARAMS((char const *));
+static void check_stdout PARAMS((void));
+static void usage PARAMS((void));
+
+/* Nonzero for -r: if comparing two directories,
+   compare their common subdirectories recursively.  */
+
+static int recursive;
+
+/* For debugging: don't do discard_confusing_lines.  */
+
+int no_discards;
+
+#if HAVE_SETMODE
+/* I/O mode: nonzero only if using binary input/output.  */
+static int binary_I_O;
+#endif
+
+/* Return a string containing the command options with which diff was invoked.
+   Spaces appear between what were separate ARGV-elements.
+   There is a space at the beginning but none at the end.
+   If there were no options, the result is an empty string.
+
+   Arguments: OPTIONVEC, a vector containing separate ARGV-elements, and COUNT,
+   the length of that vector.  */
+
+static char *
+option_list (optionvec, count)
+     char **optionvec;  /* Was `vector', but that collides on Alliant.  */
+     int count;
+{
+  int i;
+  size_t length = 0;
+  char *result;
+
+  for (i = 0; i < count; i++)
+    length += strlen (optionvec[i]) + 1;
+
+  result = xmalloc (length + 1);
+  result[0] = 0;
+
+  for (i = 0; i < count; i++)
+    {
+      strcat (result, " ");
+      strcat (result, optionvec[i]);
+    }
+
+  return result;
+}
+
+/* Convert STR to a positive integer, storing the result in *OUT.
+   If STR is not a valid integer, return -1 (otherwise 0). */
+static int
+ck_atoi (str, out)
+     char const *str;
+     int *out;
+{
+  char const *p;
+  for (p = str; *p; p++)
+    if (*p < '0' || *p > '9')
+      return -1;
+
+  *out = atoi (optarg);
+  return 0;
+}
+
+/* Keep track of excluded file name patterns.  */
+
+static char const **exclude;
+static int exclude_alloc, exclude_count;
+
+int
+excluded_filename (f)
+     char const *f;
+{
+  int i;
+  for (i = 0;  i < exclude_count;  i++)
+    if (fnmatch (exclude[i], f, 0) == 0)
+      return 1;
+  return 0;
+}
+
+static void
+add_exclude (pattern)
+     char const *pattern;
+{
+  if (exclude_alloc <= exclude_count)
+    exclude = (char const **)
+	      (exclude_alloc == 0
+	       ? xmalloc ((exclude_alloc = 64) * sizeof (*exclude))
+	       : xrealloc (exclude, (exclude_alloc *= 2) * sizeof (*exclude)));
+
+  exclude[exclude_count++] = pattern;
+}
+
+static int
+add_exclude_file (name)
+     char const *name;
+{
+  struct file_data f;
+  char *p, *q, *lim;
+
+  f.name = optarg;
+  f.desc = (strcmp (optarg, "-") == 0
+	    ? STDIN_FILENO
+	    : open (optarg, O_RDONLY, 0));
+  if (f.desc < 0 || fstat (f.desc, &f.stat) != 0)
+    return -1;
+
+  sip (&f, 1);
+  slurp (&f);
+
+  for (p = f.buffer, lim = p + f.buffered_chars;  p < lim;  p = q)
+    {
+      q = (char *) memchr (p, '\n', lim - p);
+      if (!q)
+	q = lim;
+      *q++ = 0;
+      add_exclude (p);
+    }
+
+  return close (f.desc);
+}
+
+/* The numbers 129- that appear in the fourth element of some entries
+   tell the big switch in `main' how to process those options.  */
+
+static struct option const longopts[] =
+{
+  {"ignore-blank-lines", 0, 0, 'B'},
+  {"context", 2, 0, 'C'},
+  {"ifdef", 1, 0, 'D'},
+  {"show-function-line", 1, 0, 'F'},
+  {"speed-large-files", 0, 0, 'H'},
+  {"ignore-matching-lines", 1, 0, 'I'},
+  {"label", 1, 0, 'L'},
+  {"file-label", 1, 0, 'L'},	/* An alias, no longer recommended */
+  {"new-file", 0, 0, 'N'},
+  {"entire-new-file", 0, 0, 'N'},	/* An alias, no longer recommended */
+  {"unidirectional-new-file", 0, 0, 'P'},
+  {"starting-file", 1, 0, 'S'},
+  {"initial-tab", 0, 0, 'T'},
+  {"width", 1, 0, 'W'},
+  {"text", 0, 0, 'a'},
+  {"ascii", 0, 0, 'a'},		/* An alias, no longer recommended */
+  {"ignore-space-change", 0, 0, 'b'},
+  {"minimal", 0, 0, 'd'},
+  {"ed", 0, 0, 'e'},
+  {"forward-ed", 0, 0, 'f'},
+  {"ignore-case", 0, 0, 'i'},
+  {"paginate", 0, 0, 'l'},
+  {"print", 0, 0, 'l'},		/* An alias, no longer recommended */
+  {"rcs", 0, 0, 'n'},
+  {"show-c-function", 0, 0, 'p'},
+  {"brief", 0, 0, 'q'},
+  {"recursive", 0, 0, 'r'},
+  {"report-identical-files", 0, 0, 's'},
+  {"expand-tabs", 0, 0, 't'},
+  {"version", 0, 0, 'v'},
+  {"ignore-all-space", 0, 0, 'w'},
+  {"exclude", 1, 0, 'x'},
+  {"exclude-from", 1, 0, 'X'},
+  {"side-by-side", 0, 0, 'y'},
+  {"unified", 2, 0, 'U'},
+  {"left-column", 0, 0, 129},
+  {"suppress-common-lines", 0, 0, 130},
+  {"sdiff-merge-assist", 0, 0, 131},
+  {"old-line-format", 1, 0, 132},
+  {"new-line-format", 1, 0, 133},
+  {"unchanged-line-format", 1, 0, 134},
+  {"line-format", 1, 0, 135},
+  {"old-group-format", 1, 0, 136},
+  {"new-group-format", 1, 0, 137},
+  {"unchanged-group-format", 1, 0, 138},
+  {"changed-group-format", 1, 0, 139},
+  {"horizon-lines", 1, 0, 140},
+  {"help", 0, 0, 141},
+  {"binary", 0, 0, 142},
+  {0, 0, 0, 0}
+};
+
+int
+main (argc, argv)
+     int argc;
+     char *argv[];
+{
+  int val;
+  int c;
+  int prev = -1;
+  int width = DEFAULT_WIDTH;
+  int show_c_function = 0;
+
+  /* Do our initializations.  */
+  initialize_main (&argc, &argv);
+  program_name = argv[0];
+  output_style = OUTPUT_NORMAL;
+  context = -1;
+
+  /* Decode the options.  */
+
+  while ((c = getopt_long (argc, argv,
+			   "0123456789abBcC:dD:efF:hHiI:lL:nNpPqrsS:tTuU:vwW:x:X:y",
+			   longopts, 0)) != EOF)
+    {
+      switch (c)
+	{
+	  /* All digits combine in decimal to specify the context-size.  */
+	case '1':
+	case '2':
+	case '3':
+	case '4':
+	case '5':
+	case '6':
+	case '7':
+	case '8':
+	case '9':
+	case '0':
+	  if (context == -1)
+	    context = 0;
+	  /* If a context length has already been specified,
+	     more digits allowed only if they follow right after the others.
+	     Reject two separate runs of digits, or digits after -C.  */
+	  else if (prev < '0' || prev > '9')
+	    fatal ("context length specified twice");
+
+	  context = context * 10 + c - '0';
+	  break;
+
+	case 'a':
+	  /* Treat all files as text files; never treat as binary.  */
+	  always_text_flag = 1;
+	  break;
+
+	case 'b':
+	  /* Ignore changes in amount of white space.  */
+	  ignore_space_change_flag = 1;
+	  ignore_some_changes = 1;
+	  ignore_some_line_changes = 1;
+	  break;
+
+	case 'B':
+	  /* Ignore changes affecting only blank lines.  */
+	  ignore_blank_lines_flag = 1;
+	  ignore_some_changes = 1;
+	  break;
+
+	case 'C':		/* +context[=lines] */
+	case 'U':		/* +unified[=lines] */
+	  if (optarg)
+	    {
+	      if (context >= 0)
+		fatal ("context length specified twice");
+
+	      if (ck_atoi (optarg, &context))
+		fatal ("invalid context length argument");
+	    }
+
+	  /* Falls through.  */
+	case 'c':
+	  /* Make context-style output.  */
+	  specify_style (c == 'U' ? OUTPUT_UNIFIED : OUTPUT_CONTEXT);
+	  break;
+
+	case 'd':
+	  /* Don't discard lines.  This makes things slower (sometimes much
+	     slower) but will find a guaranteed minimal set of changes.  */
+	  no_discards = 1;
+	  break;
+
+	case 'D':
+	  /* Make merged #ifdef output.  */
+	  specify_style (OUTPUT_IFDEF);
+	  {
+	    int i, err = 0;
+	    static char const C_ifdef_group_formats[] =
+	      "#ifndef %s\n%%<#endif /* not %s */\n%c#ifdef %s\n%%>#endif /* %s */\n%c%%=%c#ifndef %s\n%%<#else /* %s */\n%%>#endif /* %s */\n";
+	    char *b = xmalloc (sizeof (C_ifdef_group_formats)
+			       + 7 * strlen(optarg) - 14 /* 7*"%s" */
+			       - 8 /* 5*"%%" + 3*"%c" */);
+	    sprintf (b, C_ifdef_group_formats,
+		     optarg, optarg, 0,
+		     optarg, optarg, 0, 0,
+		     optarg, optarg, optarg);
+	    for (i = 0; i < 4; i++)
+	      {
+		err |= specify_format (&group_format[i], b);
+		b += strlen (b) + 1;
+	      }
+	    if (err)
+	      error ("conflicting #ifdef formats", 0, 0);
+	  }
+	  break;
+
+	case 'e':
+	  /* Make output that is a valid `ed' script.  */
+	  specify_style (OUTPUT_ED);
+	  break;
+
+	case 'f':
+	  /* Make output that looks vaguely like an `ed' script
+	     but has changes in the order they appear in the file.  */
+	  specify_style (OUTPUT_FORWARD_ED);
+	  break;
+
+	case 'F':
+	  /* Show, for each set of changes, the previous line that
+	     matches the specified regexp.  Currently affects only
+	     context-style output.  */
+	  add_regexp (&function_regexp_list, optarg);
+	  break;
+
+	case 'h':
+	  /* Split the files into chunks of around 1500 lines
+	     for faster processing.  Usually does not change the result.
+
+	     This currently has no effect.  */
+	  break;
+
+	case 'H':
+	  /* Turn on heuristics that speed processing of large files
+	     with a small density of changes.  */
+	  heuristic = 1;
+	  break;
+
+	case 'i':
+	  /* Ignore changes in case.  */
+	  ignore_case_flag = 1;
+	  ignore_some_changes = 1;
+	  ignore_some_line_changes = 1;
+	  break;
+
+	case 'I':
+	  /* Ignore changes affecting only lines that match the
+	     specified regexp.  */
+	  add_regexp (&ignore_regexp_list, optarg);
+	  ignore_some_changes = 1;
+	  break;
+
+	case 'l':
+	  /* Pass the output through `pr' to paginate it.  */
+	  paginate_flag = 1;
+#if !defined(SIGCHLD) && defined(SIGCLD)
+#define SIGCHLD SIGCLD
+#endif
+#ifdef SIGCHLD
+	  /* Pagination requires forking and waiting, and
+	     System V fork+wait does not work if SIGCHLD is ignored.  */
+	  signal (SIGCHLD, SIG_DFL);
+#endif
+	  break;
+
+	case 'L':
+	  /* Specify file labels for `-c' output headers.  */
+	  if (!file_label[0])
+	    file_label[0] = optarg;
+	  else if (!file_label[1])
+	    file_label[1] = optarg;
+	  else
+	    fatal ("too many file label options");
+	  break;
+
+	case 'n':
+	  /* Output RCS-style diffs, like `-f' except that each command
+	     specifies the number of lines affected.  */
+	  specify_style (OUTPUT_RCS);
+	  break;
+
+	case 'N':
+	  /* When comparing directories, if a file appears only in one
+	     directory, treat it as present but empty in the other.  */
+	  entire_new_file_flag = 1;
+	  break;
+
+	case 'p':
+	  /* Make context-style output and show name of last C function.  */
+	  show_c_function = 1;
+	  add_regexp (&function_regexp_list, "^[_a-zA-Z$]");
+	  break;
+
+	case 'P':
+	  /* When comparing directories, if a file appears only in
+	     the second directory of the two,
+	     treat it as present but empty in the other.  */
+	  unidirectional_new_file_flag = 1;
+	  break;
+
+	case 'q':
+	  no_details_flag = 1;
+	  break;
+
+	case 'r':
+	  /* When comparing directories,
+	     recursively compare any subdirectories found.  */
+	  recursive = 1;
+	  break;
+
+	case 's':
+	  /* Print a message if the files are the same.  */
+	  print_file_same_flag = 1;
+	  break;
+
+	case 'S':
+	  /* When comparing directories, start with the specified
+	     file name.  This is used for resuming an aborted comparison.  */
+	  dir_start_file = optarg;
+	  break;
+
+	case 't':
+	  /* Expand tabs to spaces in the output so that it preserves
+	     the alignment of the input files.  */
+	  tab_expand_flag = 1;
+	  break;
+
+	case 'T':
+	  /* Use a tab in the output, rather than a space, before the
+	     text of an input line, so as to keep the proper alignment
+	     in the input line without changing the characters in it.  */
+	  tab_align_flag = 1;
+	  break;
+
+	case 'u':
+	  /* Output the context diff in unidiff format.  */
+	  specify_style (OUTPUT_UNIFIED);
+	  break;
+
+	case 'v':
+	  printf ("diff - GNU diffutils version %s\n", version_string);
+	  exit (0);
+
+	case 'w':
+	  /* Ignore horizontal white space when comparing lines.  */
+	  ignore_all_space_flag = 1;
+	  ignore_some_changes = 1;
+	  ignore_some_line_changes = 1;
+	  break;
+
+	case 'x':
+	  add_exclude (optarg);
+	  break;
+
+	case 'X':
+	  if (add_exclude_file (optarg) != 0)
+	    pfatal_with_name (optarg);
+	  break;
+
+	case 'y':
+	  /* Use side-by-side (sdiff-style) columnar output. */
+	  specify_style (OUTPUT_SDIFF);
+	  break;
+
+	case 'W':
+	  /* Set the line width for OUTPUT_SDIFF.  */
+	  if (ck_atoi (optarg, &width) || width <= 0)
+	    fatal ("column width must be a positive integer");
+	  break;
+
+	case 129:
+	  sdiff_left_only = 1;
+	  break;
+
+	case 130:
+	  sdiff_skip_common_lines = 1;
+	  break;
+
+	case 131:
+	  /* sdiff-style columns output. */
+	  specify_style (OUTPUT_SDIFF);
+	  sdiff_help_sdiff = 1;
+	  break;
+
+	case 132:
+	case 133:
+	case 134:
+	  specify_style (OUTPUT_IFDEF);
+	  if (specify_format (&line_format[c - 132], optarg) != 0)
+	    error ("conflicting line format", 0, 0);
+	  break;
+
+	case 135:
+	  specify_style (OUTPUT_IFDEF);
+	  {
+	    int i, err = 0;
+	    for (i = 0; i < sizeof (line_format) / sizeof (*line_format); i++)
+	      err |= specify_format (&line_format[i], optarg);
+	    if (err)
+	      error ("conflicting line format", 0, 0);
+	  }
+	  break;
+
+	case 136:
+	case 137:
+	case 138:
+	case 139:
+	  specify_style (OUTPUT_IFDEF);
+	  if (specify_format (&group_format[c - 136], optarg) != 0)
+	    error ("conflicting group format", 0, 0);
+	  break;
+
+	case 140:
+	  if (ck_atoi (optarg, &horizon_lines) || horizon_lines < 0)
+	    fatal ("horizon must be a nonnegative integer");
+	  break;
+
+	case 141:
+	  usage ();
+	  check_stdout ();
+	  exit (0);
+
+	case 142:
+	  /* Use binary I/O when reading and writing data.
+	     On Posix hosts, this has no effect.  */
+#if HAVE_SETMODE
+	  binary_I_O = 1;
+	  setmode (STDOUT_FILENO, O_BINARY);
+#endif
+	  break;
+
+	default:
+	  try_help (0);
+	}
+      prev = c;
+    }
+
+  if (argc - optind != 2)
+    try_help (argc - optind < 2 ? "missing operand" : "extra operand");
+
+
+  {
+    /*
+     *	We maximize first the half line width, and then the gutter width,
+     *	according to the following constraints:
+     *	1.  Two half lines plus a gutter must fit in a line.
+     *	2.  If the half line width is nonzero:
+     *	    a.  The gutter width is at least GUTTER_WIDTH_MINIMUM.
+     *	    b.  If tabs are not expanded to spaces,
+     *		a half line plus a gutter is an integral number of tabs,
+     *		so that tabs in the right column line up.
+     */
+    int t = tab_expand_flag ? 1 : TAB_WIDTH;
+    int off = (width + t + GUTTER_WIDTH_MINIMUM) / (2*t)  *  t;
+    sdiff_half_width = max (0, min (off - GUTTER_WIDTH_MINIMUM, width - off)),
+    sdiff_column2_offset = sdiff_half_width ? off : width;
+  }
+
+  if (show_c_function && output_style != OUTPUT_UNIFIED)
+    specify_style (OUTPUT_CONTEXT);
+
+  if (output_style != OUTPUT_CONTEXT && output_style != OUTPUT_UNIFIED)
+    context = 0;
+  else if (context == -1)
+    /* Default amount of context for -c.  */
+    context = 3;
+
+  if (output_style == OUTPUT_IFDEF)
+    {
+      /* Format arrays are char *, not char const *,
+	 because integer formats are temporarily modified.
+	 But it is safe to assign a constant like "%=" to a format array,
+	 since "%=" does not format any integers.  */
+      int i;
+      for (i = 0; i < sizeof (line_format) / sizeof (*line_format); i++)
+	if (!line_format[i])
+	  line_format[i] = "%l\n";
+      if (!group_format[OLD])
+	group_format[OLD]
+	  = group_format[UNCHANGED] ? group_format[UNCHANGED] : "%<";
+      if (!group_format[NEW])
+	group_format[NEW]
+	  = group_format[UNCHANGED] ? group_format[UNCHANGED] : "%>";
+      if (!group_format[UNCHANGED])
+	group_format[UNCHANGED] = "%=";
+      if (!group_format[CHANGED])
+	group_format[CHANGED] = concat (group_format[OLD],
+					group_format[NEW], "");
+    }
+
+  no_diff_means_no_output =
+    (output_style == OUTPUT_IFDEF ?
+      (!*group_format[UNCHANGED]
+       || (strcmp (group_format[UNCHANGED], "%=") == 0
+	   && !*line_format[UNCHANGED]))
+     : output_style == OUTPUT_SDIFF ? sdiff_skip_common_lines : 1);
+
+  switch_string = option_list (argv + 1, optind - 1);
+
+  val = compare_files (0, argv[optind], 0, argv[optind + 1], 0);
+
+  /* Print any messages that were saved up for last.  */
+  print_message_queue ();
+
+  check_stdout ();
+  exit (val);
+  return val;
+}
+
+/* Add the compiled form of regexp PATTERN to REGLIST.  */
+
+static void
+add_regexp (reglist, pattern)
+     struct regexp_list **reglist;
+     char const *pattern;
+{
+  struct regexp_list *r;
+  char const *m;
+
+  r = (struct regexp_list *) xmalloc (sizeof (*r));
+  bzero (r, sizeof (*r));
+  r->buf.fastmap = xmalloc (256);
+  m = re_compile_pattern (pattern, strlen (pattern), &r->buf);
+  if (m != 0)
+    error ("%s: %s", pattern, m);
+
+  /* Add to the start of the list, since it's easier than the end.  */
+  r->next = *reglist;
+  *reglist = r;
+}
+
+static void
+try_help (reason)
+     char const *reason;
+{
+  if (reason)
+    error ("%s", reason, 0);
+  error ("Try `%s --help' for more information.", program_name, 0);
+  exit (2);
+}
+
+static void
+check_stdout ()
+{
+  if (ferror (stdout) || fclose (stdout) != 0)
+    fatal ("write error");
+}
+
+static char const * const option_help[] = {
+"-i  --ignore-case  Consider upper- and lower-case to be the same.",
+"-w  --ignore-all-space  Ignore all white space.",
+"-b  --ignore-space-change  Ignore changes in the amount of white space.",
+"-B  --ignore-blank-lines  Ignore changes whose lines are all blank.",
+"-I RE  --ignore-matching-lines=RE  Ignore changes whose lines all match RE.",
+#if HAVE_SETMODE
+"--binary  Read and write data in binary mode.",
+#endif
+"-a  --text  Treat all files as text.\n",
+"-c  -C NUM  --context[=NUM]  Output NUM (default 2) lines of copied context.",
+"-u  -U NUM  --unified[=NUM]  Output NUM (default 2) lines of unified context.",
+"  -NUM  Use NUM context lines.",
+"  -L LABEL  --label LABEL  Use LABEL instead of file name.",
+"  -p  --show-c-function  Show which C function each change is in.",
+"  -F RE  --show-function-line=RE  Show the most recent line matching RE.",
+"-q  --brief  Output only whether files differ.",
+"-e  --ed  Output an ed script.",
+"-n  --rcs  Output an RCS format diff.",
+"-y  --side-by-side  Output in two columns.",
+"  -w NUM  --width=NUM  Output at most NUM (default 130) characters per line.",
+"  --left-column  Output only the left column of common lines.",
+"  --suppress-common-lines  Do not output common lines.",
+"-DNAME  --ifdef=NAME  Output merged file to show `#ifdef NAME' diffs.",
+"--GTYPE-group-format=GFMT  Similar, but format GTYPE input groups with GFMT.",
+"--line-format=LFMT  Similar, but format all input lines with LFMT.",
+"--LTYPE-line-format=LFMT  Similar, but format LTYPE input lines with LFMT.",
+"  LTYPE is `old', `new', or `unchanged'.  GTYPE is LTYPE or `changed'.",
+"  GFMT may contain:",
+"    %<  lines from FILE1",
+"    %>  lines from FILE2",
+"    %=  lines common to FILE1 and FILE2",
+"    %[-][WIDTH][.[PREC]]{doxX}LETTER  printf-style spec for LETTER",
+"      LETTERs are as follows for new group, lower case for old group:",
+"        F  first line number",
+"        L  last line number",
+"        N  number of lines = L-F+1",
+"        E  F-1",
+"        M  L+1",
+"  LFMT may contain:",
+"    %L  contents of line",
+"    %l  contents of line, excluding any trailing newline",
+"    %[-][WIDTH][.[PREC]]{doxX}n  printf-style spec for input line number",
+"  Either GFMT or LFMT may contain:",
+"    %%  %",
+"    %c'C'  the single character C",
+"    %c'\\OOO'  the character with octal code OOO\n",
+"-l  --paginate  Pass the output through `pr' to paginate it.",
+"-t  --expand-tabs  Expand tabs to spaces in output.",
+"-T  --initial-tab  Make tabs line up by prepending a tab.\n",
+"-r  --recursive  Recursively compare any subdirectories found.",
+"-N  --new-file  Treat absent files as empty.",
+"-P  --unidirectional-new-file  Treat absent first files as empty.",
+"-s  --report-identical-files  Report when two files are the same.",
+"-x PAT  --exclude=PAT  Exclude files that match PAT.",
+"-X FILE  --exclude-from=FILE  Exclude files that match any pattern in FILE.",
+"-S FILE  --starting-file=FILE  Start with FILE when comparing directories.\n",
+"--horizon-lines=NUM  Keep NUM lines of the common prefix and suffix.",
+"-d  --minimal  Try hard to find a smaller set of changes.",
+"-H  --speed-large-files  Assume large files and many scattered small changes.\n",
+"-v  --version  Output version info.",
+"--help  Output this help.",
+0
+};
+
+static void
+usage ()
+{
+  char const * const *p;
+
+  printf ("Usage: %s [OPTION]... FILE1 FILE2\n\n", program_name);
+  for (p = option_help;  *p;  p++)
+    printf ("  %s\n", *p);
+  printf ("\nIf FILE1 or FILE2 is `-', read standard input.\n");
+}
+
+static int
+specify_format (var, value)
+     char **var;
+     char *value;
+{
+  int err = *var ? strcmp (*var, value) : 0;
+  *var = value;
+  return err;
+}
+
+static void
+specify_style (style)
+     enum output_style style;
+{
+  if (output_style != OUTPUT_NORMAL
+      && output_style != style)
+    error ("conflicting specifications of output style", 0, 0);
+  output_style = style;
+}
+
+static char const *
+filetype (st)
+     struct stat const *st;
+{
+  /* See Posix.2 section 4.17.6.1.1 and Table 5-1 for these formats.
+     To keep diagnostics grammatical, the returned string must start
+     with a consonant.  */
+
+  if (S_ISREG (st->st_mode))
+    {
+      if (st->st_size == 0)
+	return "regular empty file";
+      /* Posix.2 section 5.14.2 seems to suggest that we must read the file
+	 and guess whether it's C, Fortran, etc., but this is somewhat useless
+	 and doesn't reflect historical practice.  We're allowed to guess
+	 wrong, so we don't bother to read the file.  */
+      return "regular file";
+    }
+  if (S_ISDIR (st->st_mode)) return "directory";
+
+  /* other Posix.1 file types */
+#ifdef S_ISBLK
+  if (S_ISBLK (st->st_mode)) return "block special file";
+#endif
+#ifdef S_ISCHR
+  if (S_ISCHR (st->st_mode)) return "character special file";
+#endif
+#ifdef S_ISFIFO
+  if (S_ISFIFO (st->st_mode)) return "fifo";
+#endif
+
+  /* other Posix.1b file types */
+#ifdef S_TYPEISMQ
+  if (S_TYPEISMQ (st)) return "message queue";
+#endif
+#ifdef S_TYPEISSEM
+  if (S_TYPEISSEM (st)) return "semaphore";
+#endif
+#ifdef S_TYPEISSHM
+  if (S_TYPEISSHM (st)) return "shared memory object";
+#endif
+
+  /* other popular file types */
+  /* S_ISLNK is impossible with `fstat' and `stat'.  */
+#ifdef S_ISSOCK
+  if (S_ISSOCK (st->st_mode)) return "socket";
+#endif
+
+  return "weird file";
+}
+
+/* Compare two files (or dirs) with specified names
+   DIR0/NAME0 and DIR1/NAME1, at level DEPTH in directory recursion.
+   (if DIR0 is 0, then the name is just NAME0, etc.)
+   This is self-contained; it opens the files and closes them.
+
+   Value is 0 if files are the same, 1 if different,
+   2 if there is a problem opening them.  */
+
+static int
+compare_files (dir0, name0, dir1, name1, depth)
+     char const *dir0, *dir1;
+     char const *name0, *name1;
+     int depth;
+{
+  struct file_data inf[2];
+  register int i;
+  int val;
+  int same_files;
+  int failed = 0;
+  char *free0 = 0, *free1 = 0;
+
+  /* If this is directory comparison, perhaps we have a file
+     that exists only in one of the directories.
+     If so, just print a message to that effect.  */
+
+  if (! ((name0 != 0 && name1 != 0)
+	 || (unidirectional_new_file_flag && name1 != 0)
+	 || entire_new_file_flag))
+    {
+      char const *name = name0 == 0 ? name1 : name0;
+      char const *dir = name0 == 0 ? dir1 : dir0;
+      message ("Only in %s: %s\n", dir, name);
+      /* Return 1 so that diff_dirs will return 1 ("some files differ").  */
+      return 1;
+    }
+
+  bzero (inf, sizeof (inf));
+
+  /* Mark any nonexistent file with -1 in the desc field.  */
+  /* Mark unopened files (e.g. directories) with -2. */
+
+  inf[0].desc = name0 == 0 ? -1 : -2;
+  inf[1].desc = name1 == 0 ? -1 : -2;
+
+  /* Now record the full name of each file, including nonexistent ones.  */
+
+  if (name0 == 0)
+    name0 = name1;
+  if (name1 == 0)
+    name1 = name0;
+
+  inf[0].name = dir0 == 0 ? name0 : (free0 = dir_file_pathname (dir0, name0));
+  inf[1].name = dir1 == 0 ? name1 : (free1 = dir_file_pathname (dir1, name1));
+
+  /* Stat the files.  Record whether they are directories.  */
+
+  for (i = 0; i <= 1; i++)
+    {
+      if (inf[i].desc != -1)
+	{
+	  int stat_result;
+
+	  if (i && filename_cmp (inf[i].name, inf[0].name) == 0)
+	    {
+	      inf[i].stat = inf[0].stat;
+	      stat_result = 0;
+	    }
+	  else if (strcmp (inf[i].name, "-") == 0)
+	    {
+	      inf[i].desc = STDIN_FILENO;
+	      stat_result = fstat (STDIN_FILENO, &inf[i].stat);
+	      if (stat_result == 0 && S_ISREG (inf[i].stat.st_mode))
+		{
+		  off_t pos = lseek (STDIN_FILENO, (off_t) 0, SEEK_CUR);
+		  if (pos == -1)
+		    stat_result = -1;
+		  else
+		    {
+		      if (pos <= inf[i].stat.st_size)
+			inf[i].stat.st_size -= pos;
+		      else
+			inf[i].stat.st_size = 0;
+		      /* Posix.2 4.17.6.1.4 requires current time for stdin.  */
+		      time (&inf[i].stat.st_mtime);
+		    }
+		}
+	    }
+	  else
+	    stat_result = stat (inf[i].name, &inf[i].stat);
+
+	  if (stat_result != 0)
+	    {
+	      perror_with_name (inf[i].name);
+	      failed = 1;
+	    }
+	  else
+	    {
+	      inf[i].dir_p = S_ISDIR (inf[i].stat.st_mode) && inf[i].desc != 0;
+	      if (inf[1 - i].desc == -1)
+		{
+		  inf[1 - i].dir_p = inf[i].dir_p;
+		  inf[1 - i].stat.st_mode = inf[i].stat.st_mode;
+		}
+	    }
+	}
+    }
+
+  if (! failed && depth == 0 && inf[0].dir_p != inf[1].dir_p)
+    {
+      /* If one is a directory, and it was specified in the command line,
+	 use the file in that dir with the other file's basename.  */
+
+      int fnm_arg = inf[0].dir_p;
+      int dir_arg = 1 - fnm_arg;
+      char const *fnm = inf[fnm_arg].name;
+      char const *dir = inf[dir_arg].name;
+      char const *p = filename_lastdirchar (fnm);
+      char const *filename = inf[dir_arg].name
+	= dir_file_pathname (dir, p ? p + 1 : fnm);
+
+      if (strcmp (fnm, "-") == 0)
+	fatal ("can't compare - to a directory");
+
+      if (stat (filename, &inf[dir_arg].stat) != 0)
+	{
+	  perror_with_name (filename);
+	  failed = 1;
+	}
+      else
+	inf[dir_arg].dir_p = S_ISDIR (inf[dir_arg].stat.st_mode);
+    }
+
+  if (failed)
+    {
+
+      /* If either file should exist but does not, return 2.  */
+
+      val = 2;
+
+    }
+  else if ((same_files = inf[0].desc != -1 && inf[1].desc != -1
+			 && 0 < same_file (&inf[0].stat, &inf[1].stat))
+	   && no_diff_means_no_output)
+    {
+      /* The two named files are actually the same physical file.
+	 We know they are identical without actually reading them.  */
+
+      val = 0;
+    }
+  else if (inf[0].dir_p & inf[1].dir_p)
+    {
+      if (output_style == OUTPUT_IFDEF)
+	fatal ("-D option not supported with directories");
+
+      /* If both are directories, compare the files in them.  */
+
+      if (depth > 0 && !recursive)
+	{
+	  /* But don't compare dir contents one level down
+	     unless -r was specified.  */
+	  message ("Common subdirectories: %s and %s\n",
+		   inf[0].name, inf[1].name);
+	  val = 0;
+	}
+      else
+	{
+	  val = diff_dirs (inf, compare_files, depth);
+	}
+
+    }
+  else if ((inf[0].dir_p | inf[1].dir_p)
+	   || (depth > 0
+	       && (! S_ISREG (inf[0].stat.st_mode)
+		   || ! S_ISREG (inf[1].stat.st_mode))))
+    {
+      /* Perhaps we have a subdirectory that exists only in one directory.
+	 If so, just print a message to that effect.  */
+
+      if (inf[0].desc == -1 || inf[1].desc == -1)
+	{
+	  if ((inf[0].dir_p | inf[1].dir_p)
+	      && recursive
+	      && (entire_new_file_flag
+		  || (unidirectional_new_file_flag && inf[0].desc == -1)))
+	    val = diff_dirs (inf, compare_files, depth);
+	  else
+	    {
+	      char const *dir = (inf[0].desc == -1) ? dir1 : dir0;
+	      /* See Posix.2 section 4.17.6.1.1 for this format.  */
+	      message ("Only in %s: %s\n", dir, name0);
+	      val = 1;
+	    }
+	}
+      else
+	{
+	  /* We have two files that are not to be compared.  */
+
+	  /* See Posix.2 section 4.17.6.1.1 for this format.  */
+	  message5 ("File %s is a %s while file %s is a %s\n",
+		    inf[0].name, filetype (&inf[0].stat),
+		    inf[1].name, filetype (&inf[1].stat));
+
+	  /* This is a difference.  */
+	  val = 1;
+	}
+    }
+  else if ((no_details_flag & ~ignore_some_changes)
+	   && inf[0].stat.st_size != inf[1].stat.st_size
+	   && (inf[0].desc == -1 || S_ISREG (inf[0].stat.st_mode))
+	   && (inf[1].desc == -1 || S_ISREG (inf[1].stat.st_mode)))
+    {
+      message ("Files %s and %s differ\n", inf[0].name, inf[1].name);
+      val = 1;
+    }
+  else
+    {
+      /* Both exist and neither is a directory.  */
+
+      /* Open the files and record their descriptors.  */
+
+      if (inf[0].desc == -2)
+	if ((inf[0].desc = open (inf[0].name, O_RDONLY, 0)) < 0)
+	  {
+	    perror_with_name (inf[0].name);
+	    failed = 1;
+	  }
+      if (inf[1].desc == -2)
+	if (same_files)
+	  inf[1].desc = inf[0].desc;
+	else if ((inf[1].desc = open (inf[1].name, O_RDONLY, 0)) < 0)
+	  {
+	    perror_with_name (inf[1].name);
+	    failed = 1;
+	  }
+
+#if HAVE_SETMODE
+      if (binary_I_O)
+	for (i = 0; i <= 1; i++)
+	  if (0 <= inf[i].desc)
+	    setmode (inf[i].desc, O_BINARY);
+#endif
+
+      /* Compare the files, if no error was found.  */
+
+      val = failed ? 2 : diff_2_files (inf, depth);
+
+      /* Close the file descriptors.  */
+
+      if (inf[0].desc >= 0 && close (inf[0].desc) != 0)
+	{
+	  perror_with_name (inf[0].name);
+	  val = 2;
+	}
+      if (inf[1].desc >= 0 && inf[0].desc != inf[1].desc
+	  && close (inf[1].desc) != 0)
+	{
+	  perror_with_name (inf[1].name);
+	  val = 2;
+	}
+    }
+
+  /* Now the comparison has been done, if no error prevented it,
+     and VAL is the value this function will return.  */
+
+  if (val == 0 && !inf[0].dir_p)
+    {
+      if (print_file_same_flag)
+	message ("Files %s and %s are identical\n",
+		 inf[0].name, inf[1].name);
+    }
+  else
+    fflush (stdout);
+
+  if (free0)
+    free (free0);
+  if (free1)
+    free (free1);
+
+  return val;
+}
diff --git a/gnu/usr.bin/diff/diff.h b/gnu/usr.bin/diff/diff.h
new file mode 100644
index 00000000000..66c6940c72b
--- /dev/null
+++ b/gnu/usr.bin/diff/diff.h
@@ -0,0 +1,340 @@
+/* Shared definitions for GNU DIFF
+   Copyright (C) 1988, 89, 91, 92, 93 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "system.h"
+#include <stdio.h>
+#include "regex.h"
+
+#define TAB_WIDTH 8
+
+/* Variables for command line options */
+
+#ifndef GDIFF_MAIN
+#define EXTERN extern
+#else
+#define EXTERN
+#endif
+
+enum output_style {
+  /* Default output style.  */
+  OUTPUT_NORMAL,
+  /* Output the differences with lines of context before and after (-c).  */
+  OUTPUT_CONTEXT,
+  /* Output the differences in a unified context diff format (-u). */
+  OUTPUT_UNIFIED,
+  /* Output the differences as commands suitable for `ed' (-e).  */
+  OUTPUT_ED,
+  /* Output the diff as a forward ed script (-f).  */
+  OUTPUT_FORWARD_ED,
+  /* Like -f, but output a count of changed lines in each "command" (-n). */
+  OUTPUT_RCS,
+  /* Output merged #ifdef'd file (-D).  */
+  OUTPUT_IFDEF,
+  /* Output sdiff style (-y).  */
+  OUTPUT_SDIFF
+};
+
+/* True for output styles that are robust,
+   i.e. can handle a file that ends in a non-newline.  */
+#define ROBUST_OUTPUT_STYLE(S) ((S) != OUTPUT_ED && (S) != OUTPUT_FORWARD_ED)
+
+EXTERN enum output_style output_style;
+
+/* Nonzero if output cannot be generated for identical files.  */
+EXTERN int no_diff_means_no_output;
+
+/* Number of lines of context to show in each set of diffs.
+   This is zero when context is not to be shown.  */
+EXTERN int      context;
+
+/* Consider all files as text files (-a).
+   Don't interpret codes over 0177 as implying a "binary file".  */
+EXTERN int	always_text_flag;
+
+/* Number of lines to keep in identical prefix and suffix.  */
+EXTERN int      horizon_lines;
+
+/* Ignore changes in horizontal white space (-b).  */
+EXTERN int      ignore_space_change_flag;
+
+/* Ignore all horizontal white space (-w).  */
+EXTERN int      ignore_all_space_flag;
+
+/* Ignore changes that affect only blank lines (-B).  */
+EXTERN int      ignore_blank_lines_flag;
+
+/* 1 if lines may match even if their contents do not match exactly.
+   This depends on various options.  */
+EXTERN int      ignore_some_line_changes;
+
+/* 1 if files may match even if their contents are not byte-for-byte identical.
+   This depends on various options.  */
+EXTERN int      ignore_some_changes;
+
+/* Ignore differences in case of letters (-i).  */
+EXTERN int      ignore_case_flag;
+
+/* File labels for `-c' output headers (-L).  */
+EXTERN char *file_label[2];
+
+struct regexp_list
+{
+  struct re_pattern_buffer buf;
+  struct regexp_list *next;
+};
+
+/* Regexp to identify function-header lines (-F).  */
+EXTERN struct regexp_list *function_regexp_list;
+
+/* Ignore changes that affect only lines matching this regexp (-I).  */
+EXTERN struct regexp_list *ignore_regexp_list;
+
+/* Say only whether files differ, not how (-q).  */
+EXTERN int 	no_details_flag;
+
+/* Report files compared that match (-s).
+   Normally nothing is output when that happens.  */
+EXTERN int      print_file_same_flag;
+
+/* Output the differences with exactly 8 columns added to each line
+   so that any tabs in the text line up properly (-T).  */
+EXTERN int	tab_align_flag;
+
+/* Expand tabs in the output so the text lines up properly
+   despite the characters added to the front of each line (-t).  */
+EXTERN int	tab_expand_flag;
+
+/* In directory comparison, specify file to start with (-S).
+   All file names less than this name are ignored.  */
+EXTERN char	*dir_start_file;
+
+/* If a file is new (appears in only one dir)
+   include its entire contents (-N).
+   Then `patch' would create the file with appropriate contents.  */
+EXTERN int	entire_new_file_flag;
+
+/* If a file is new (appears in only the second dir)
+   include its entire contents (-P).
+   Then `patch' would create the file with appropriate contents.  */
+EXTERN int	unidirectional_new_file_flag;
+
+/* Pipe each file's output through pr (-l).  */
+EXTERN int	paginate_flag;
+
+enum line_class {
+  /* Lines taken from just the first file.  */
+  OLD,
+  /* Lines taken from just the second file.  */
+  NEW,
+  /* Lines common to both files.  */
+  UNCHANGED,
+  /* A hunk containing both old and new lines (line groups only).  */
+  CHANGED
+};
+
+/* Line group formats for old, new, unchanged, and changed groups.  */
+EXTERN char *group_format[CHANGED + 1];
+
+/* Line formats for old, new, and unchanged lines.  */
+EXTERN char *line_format[UNCHANGED + 1];
+
+/* If using OUTPUT_SDIFF print extra information to help the sdiff filter. */
+EXTERN int sdiff_help_sdiff;
+
+/* Tell OUTPUT_SDIFF to show only the left version of common lines. */
+EXTERN int sdiff_left_only;
+
+/* Tell OUTPUT_SDIFF to not show common lines. */
+EXTERN int sdiff_skip_common_lines;
+
+/* The half line width and column 2 offset for OUTPUT_SDIFF.  */
+EXTERN unsigned sdiff_half_width;
+EXTERN unsigned sdiff_column2_offset;
+
+/* String containing all the command options diff received,
+   with spaces between and at the beginning but none at the end.
+   If there were no options given, this string is empty.  */
+EXTERN char *	switch_string;
+
+/* Nonzero means use heuristics for better speed.  */
+EXTERN int	heuristic;
+
+/* Name of program the user invoked (for error messages).  */
+EXTERN char *program_name;
+
+/* The result of comparison is an "edit script": a chain of `struct change'.
+   Each `struct change' represents one place where some lines are deleted
+   and some are inserted.
+
+   LINE0 and LINE1 are the first affected lines in the two files (origin 0).
+   DELETED is the number of lines deleted here from file 0.
+   INSERTED is the number of lines inserted here in file 1.
+
+   If DELETED is 0 then LINE0 is the number of the line before
+   which the insertion was done; vice versa for INSERTED and LINE1.  */
+
+struct change
+{
+  struct change *link;		/* Previous or next edit command  */
+  int inserted;			/* # lines of file 1 changed here.  */
+  int deleted;			/* # lines of file 0 changed here.  */
+  int line0;			/* Line number of 1st deleted line.  */
+  int line1;			/* Line number of 1st inserted line.  */
+  char ignore;			/* Flag used in context.c */
+};
+
+/* Structures that describe the input files.  */
+
+/* Data on one input file being compared.  */
+
+struct file_data {
+    int             desc;	/* File descriptor  */
+    char const      *name;	/* File name  */
+    struct stat     stat;	/* File status from fstat()  */
+    int             dir_p;	/* nonzero if file is a directory  */
+
+    /* Buffer in which text of file is read.  */
+    char *	    buffer;
+    /* Allocated size of buffer.  */
+    size_t	    bufsize;
+    /* Number of valid characters now in the buffer. */
+    size_t	    buffered_chars;
+
+    /* Array of pointers to lines in the file.  */
+    char const **linbuf;
+
+    /* linbuf_base <= buffered_lines <= valid_lines <= alloc_lines.
+       linebuf[linbuf_base ... buffered_lines - 1] are possibly differing.
+       linebuf[linbuf_base ... valid_lines - 1] contain valid data.
+       linebuf[linbuf_base ... alloc_lines - 1] are allocated.  */
+    int linbuf_base, buffered_lines, valid_lines, alloc_lines;
+
+    /* Pointer to end of prefix of this file to ignore when hashing. */
+    char const *prefix_end;
+
+    /* Count of lines in the prefix.
+       There are this many lines in the file before linbuf[0].  */
+    int prefix_lines;
+
+    /* Pointer to start of suffix of this file to ignore when hashing. */
+    char const *suffix_begin;
+
+    /* Vector, indexed by line number, containing an equivalence code for
+       each line.  It is this vector that is actually compared with that
+       of another file to generate differences. */
+    int		   *equivs;
+
+    /* Vector, like the previous one except that
+       the elements for discarded lines have been squeezed out.  */
+    int		   *undiscarded;
+
+    /* Vector mapping virtual line numbers (not counting discarded lines)
+       to real ones (counting those lines).  Both are origin-0.  */
+    int		   *realindexes;
+
+    /* Total number of nondiscarded lines. */
+    int		    nondiscarded_lines;
+
+    /* Vector, indexed by real origin-0 line number,
+       containing 1 for a line that is an insertion or a deletion.
+       The results of comparison are stored here.  */
+    char	   *changed_flag;
+
+    /* 1 if file ends in a line with no final newline. */
+    int		    missing_newline;
+
+    /* 1 more than the maximum equivalence value used for this or its
+       sibling file. */
+    int equiv_max;
+};
+
+/* Describe the two files currently being compared.  */
+
+EXTERN struct file_data files[2];
+
+/* Stdio stream to output diffs to.  */
+
+EXTERN FILE *outfile;
+
+/* Declare various functions.  */
+
+/* analyze.c */
+int diff_2_files PARAMS((struct file_data[], int));
+
+/* context.c */
+void print_context_header PARAMS((struct file_data[], int));
+void print_context_script PARAMS((struct change *, int));
+
+/* diff.c */
+int excluded_filename PARAMS((char const *));
+
+/* dir.c */
+int diff_dirs PARAMS((struct file_data const[], int (*) PARAMS((char const *, char const *, char const *, char const *, int)), int));
+
+/* ed.c */
+void print_ed_script PARAMS((struct change *));
+void pr_forward_ed_script PARAMS((struct change *));
+
+/* ifdef.c */
+void print_ifdef_script PARAMS((struct change *));
+
+/* io.c */
+int read_files PARAMS((struct file_data[], int));
+int sip PARAMS((struct file_data *, int));
+void slurp PARAMS((struct file_data *));
+
+/* normal.c */
+void print_normal_script PARAMS((struct change *));
+
+/* rcs.c */
+void print_rcs_script PARAMS((struct change *));
+
+/* side.c */
+void print_sdiff_script PARAMS((struct change *));
+
+/* util.c */
+VOID *xmalloc PARAMS((size_t));
+VOID *xrealloc PARAMS((VOID *, size_t));
+char *concat PARAMS((char const *, char const *, char const *));
+char *dir_file_pathname PARAMS((char const *, char const *));
+int change_letter PARAMS((int, int));
+int line_cmp PARAMS((char const *, char const *));
+int translate_line_number PARAMS((struct file_data const *, int));
+struct change *find_change PARAMS((struct change *));
+struct change *find_reverse_change PARAMS((struct change *));
+void analyze_hunk PARAMS((struct change *, int *, int *, int *, int *, int *, int *));
+void begin_output PARAMS((void));
+void debug_script PARAMS((struct change *));
+void error PARAMS((char const *, char const *, char const *));
+void fatal PARAMS((char const *));
+void finish_output PARAMS((void));
+void message PARAMS((char const *, char const *, char const *));
+void message5 PARAMS((char const *, char const *, char const *, char const *, char const *));
+void output_1_line PARAMS((char const *, char const *, char const *, char const *));
+void perror_with_name PARAMS((char const *));
+void pfatal_with_name PARAMS((char const *));
+void print_1_line PARAMS((char const *, char const * const *));
+void print_message_queue PARAMS((void));
+void print_number_range PARAMS((int, struct file_data *, int, int));
+void print_script PARAMS((struct change *, struct change * (*) PARAMS((struct change *)), void (*) PARAMS((struct change *))));
+void setup_output PARAMS((char const *, char const *, int));
+void translate_range PARAMS((struct file_data const *, int, int, int *, int *));
+
+/* version.c */
+extern char const version_string[];
diff --git a/gnu/usr.bin/diff/diff3.1 b/gnu/usr.bin/diff/diff3.1
new file mode 100644
index 00000000000..b1903289be0
--- /dev/null
+++ b/gnu/usr.bin/diff/diff3.1
@@ -0,0 +1,207 @@
+.TH DIFF3 1 "22sep1993" "GNU Tools" "GNU Tools"
+.SH NAME
+diff3 \- find differences between three files
+.SH SYNOPSIS
+.B diff3
+[options] mine older yours
+.SH DESCRIPTION
+The
+.I diff3
+command compares three files and outputs descriptions
+of their differences.
+
+The files to compare are
+.IR mine ,
+.IR older ,
+and
+.IR yours .
+At most one of these three file names may be
+.BR \- ,
+which tells
+.I diff3
+to read the standard input for that file.
+.SS Options
+Below is a summary of all of the options that GNU
+.I diff3
+accepts.  Multiple single letter options (unless they take an argument)
+can be combined into a single command line argument.
+.TP
+.B \-a
+Treat all files as text and compare them line-by-line, even if they
+do not appear to be text.
+.TP
+.B \-A
+Incorporate all changes from
+.I older
+to
+.I yours
+into
+.IR mine ,
+surrounding all conflicts with bracket lines.
+.TP
+.B \-e
+Generate an
+.I ed
+script that incorporates all the changes from
+.I older
+to
+.I yours
+into
+.IR mine .
+.TP
+.B \-E
+Like
+.BR \-e ,
+except bracket lines from overlapping changes' first
+and third files.
+With
+.BR \-e ,
+an overlapping change looks like this:
+.sp
+.nf
+<<<<<<< \fImine\fP
+lines from \fImine\fP
+=======
+lines from \fIyours\fP
+>>>>>>> \fIyours\fP
+.fi
+.TP
+.B \-\-ed
+Generate an
+.I ed
+script that incorporates all the changes from
+.I older
+to
+.I yours
+into
+.IR mine .
+.TP
+.B \-\-easy\-only
+Like
+.BR \-e ,
+except output only the nonoverlapping changes.
+.TP
+.B \-i
+Generate
+.B w
+and
+.B q
+commands at the end of the
+.I ed
+script for System V compatibility.  This option must be combined with
+one of the
+.B \-AeExX3
+options, and may not be combined with
+.BR \-m .
+.TP
+.B \-\-initial\-tab
+Output a tab rather than two spaces before the text of a line in normal format.
+This causes the alignment of tabs in the line to look normal.
+.TP
+.BI "\-L " label
+.ns
+.TP
+.BI \-\-label= label
+Use the label
+.I label
+for the brackets output by the
+.BR \-A ,
+.B \-E
+and
+.B \-X
+options.  This option may be given up to three
+times, one for each input file.  The default labels are the names of
+the input files.  Thus
+.B "diff3 \-L X \-L Y \-L Z \-m A B C"
+acts like
+.BR "diff3 \-m A B C ,
+except that the output looks like it came from
+files named
+.BR X ,
+.B Y
+and
+.B Z
+rather than from files
+named
+.BR A ,
+.B B
+and
+.BR C .
+.TP
+.B \-m
+.br
+.ns
+.TP
+.B \-\-merge
+Apply the edit script to the first file and send the result to standard
+output.  Unlike piping the output from
+.I diff3
+to
+.IR ed ,
+this
+works even for binary files and incomplete lines.
+.B \-A
+is assumed
+if no edit script option is specified.
+.TP
+.B \-\-overlap\-only
+Like
+.BR \-e ,
+except output only the overlapping changes.
+.TP
+.B \-\-show\-all
+Incorporate all unmerged changes from
+.I older
+to
+.I yours
+into
+.IR mine ,
+surrounding all overlapping changes with bracket lines.
+.TP
+.B \-\-show\-overlap
+Like
+.BR \-e ,
+except bracket lines from overlapping changes' first
+and third files.
+.TP
+.B \-T
+Output a tab rather than two spaces before the text of a line in normal format.
+This causes the alignment of tabs in the line to look normal.
+.TP
+.B \-\-text
+Treat all files as text and compare them line-by-line, even if they
+do not appear to be text.
+.TP
+.B \-v
+.br
+.ns
+.TP
+.B \-\-version
+Output the version number of
+.IR diff3 .
+.TP
+.B \-x
+Like
+.BR \-e ,
+except output only the overlapping changes.
+.TP
+.B \-X
+Like
+.BR \-E ,
+except output only the overlapping changes.
+In other words, like
+.BR \-x ,
+except bracket changes as in
+.BR \-E .
+.TP
+.B \-3
+Like
+.BR \-e ,
+except output only the nonoverlapping changes.
+.SH SEE ALSO
+cmp(1), comm(1), diff(1), ed(1), patch(1), sdiff(1).
+.SH DIAGNOSTICS
+An exit status of 0 means
+.I diff3
+was successful, 1 means some
+conflicts were found, and 2 means trouble.
diff --git a/gnu/usr.bin/diff/diff3.c b/gnu/usr.bin/diff/diff3.c
new file mode 100644
index 00000000000..5d94ab866db
--- /dev/null
+++ b/gnu/usr.bin/diff/diff3.c
@@ -0,0 +1,1778 @@
+/* Three way file comparison program (diff3) for Project GNU.
+   Copyright (C) 1988, 1989, 1992, 1993, 1994 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* Written by Randy Smith */
+
+#include "system.h"
+#include <stdio.h>
+#include <signal.h>
+#include "getopt.h"
+
+extern char const version_string[];
+
+/*
+ * Internal data structures and macros for the diff3 program; includes
+ * data structures for both diff3 diffs and normal diffs.
+ */
+
+/* Different files within a three way diff.  */
+#define	FILE0	0
+#define	FILE1	1
+#define	FILE2	2
+
+/*
+ * A three way diff is built from two two-way diffs; the file which
+ * the two two-way diffs share is:
+ */
+#define	FILEC	FILE2
+
+/*
+ * Different files within a two way diff.
+ * FC is the common file, FO the other file.
+ */
+#define FO 0
+#define FC 1
+
+/* The ranges are indexed by */
+#define	START	0
+#define	END	1
+
+enum diff_type {
+  ERROR,			/* Should not be used */
+  ADD,				/* Two way diff add */
+  CHANGE,			/* Two way diff change */
+  DELETE,			/* Two way diff delete */
+  DIFF_ALL,			/* All three are different */
+  DIFF_1ST,			/* Only the first is different */
+  DIFF_2ND,			/* Only the second */
+  DIFF_3RD			/* Only the third */
+};
+
+/* Two way diff */
+struct diff_block {
+  int ranges[2][2];		/* Ranges are inclusive */
+  char **lines[2];		/* The actual lines (may contain nulls) */
+  size_t *lengths[2];		/* Line lengths (including newlines, if any) */
+  struct diff_block *next;
+};
+
+/* Three way diff */
+
+struct diff3_block {
+  enum diff_type correspond;	/* Type of diff */
+  int ranges[3][2];		/* Ranges are inclusive */
+  char **lines[3];		/* The actual lines (may contain nulls) */
+  size_t *lengths[3];		/* Line lengths (including newlines, if any) */
+  struct diff3_block *next;
+};
+
+/*
+ * Access the ranges on a diff block.
+ */
+#define	D_LOWLINE(diff, filenum)	\
+  ((diff)->ranges[filenum][START])
+#define	D_HIGHLINE(diff, filenum)	\
+  ((diff)->ranges[filenum][END])
+#define	D_NUMLINES(diff, filenum)	\
+  (D_HIGHLINE (diff, filenum) - D_LOWLINE (diff, filenum) + 1)
+
+/*
+ * Access the line numbers in a file in a diff by relative line
+ * numbers (i.e. line number within the diff itself).  Note that these
+ * are lvalues and can be used for assignment.
+ */
+#define	D_RELNUM(diff, filenum, linenum)	\
+  ((diff)->lines[filenum][linenum])
+#define	D_RELLEN(diff, filenum, linenum)	\
+  ((diff)->lengths[filenum][linenum])
+
+/*
+ * And get at them directly, when that should be necessary.
+ */
+#define	D_LINEARRAY(diff, filenum)	\
+  ((diff)->lines[filenum])
+#define	D_LENARRAY(diff, filenum)	\
+  ((diff)->lengths[filenum])
+
+/*
+ * Next block.
+ */
+#define	D_NEXT(diff)	((diff)->next)
+
+/*
+ * Access the type of a diff3 block.
+ */
+#define	D3_TYPE(diff)	((diff)->correspond)
+
+/*
+ * Line mappings based on diffs.  The first maps off the top of the
+ * diff, the second off of the bottom.
+ */
+#define	D_HIGH_MAPLINE(diff, fromfile, tofile, lineno)	\
+  ((lineno)						\
+   - D_HIGHLINE ((diff), (fromfile))			\
+   + D_HIGHLINE ((diff), (tofile)))
+
+#define	D_LOW_MAPLINE(diff, fromfile, tofile, lineno)	\
+  ((lineno)						\
+   - D_LOWLINE ((diff), (fromfile))			\
+   + D_LOWLINE ((diff), (tofile)))
+
+/*
+ * General memory allocation function.
+ */
+#define	ALLOCATE(number, type)	\
+  (type *) xmalloc ((number) * sizeof (type))
+
+/* Options variables for flags set on command line.  */
+
+/* If nonzero, treat all files as text files, never as binary.  */
+static int always_text;
+
+/* If nonzero, write out an ed script instead of the standard diff3 format.  */
+static int edscript;
+
+/* If nonzero, in the case of overlapping diffs (type DIFF_ALL),
+   preserve the lines which would normally be deleted from
+   file 1 with a special flagging mechanism.  */
+static int flagging;
+
+/* Number of lines to keep in identical prefix and suffix.  */
+static int horizon_lines = 10;
+
+/* Use a tab to align output lines (-T).  */
+static int tab_align_flag;
+
+/* If nonzero, do not output information for overlapping diffs.  */
+static int simple_only;
+
+/* If nonzero, do not output information for non-overlapping diffs.  */
+static int overlap_only;
+
+/* If nonzero, show information for DIFF_2ND diffs.  */
+static int show_2nd;
+
+/* If nonzero, include `:wq' at the end of the script
+   to write out the file being edited.   */
+static int finalwrite;
+
+/* If nonzero, output a merged file.  */
+static int merge;
+
+static char *program_name;
+
+static VOID *xmalloc PARAMS((size_t));
+static VOID *xrealloc PARAMS((VOID *, size_t));
+
+static char *read_diff PARAMS((char const *, char const *, char **));
+static char *scan_diff_line PARAMS((char *, char **, size_t *, char *, int));
+static enum diff_type process_diff_control PARAMS((char **, struct diff_block *));
+static int compare_line_list PARAMS((char * const[], size_t const[], char * const[], size_t const[], int));
+static int copy_stringlist PARAMS((char * const[], size_t const[], char *[], size_t[], int));
+static int dotlines PARAMS((FILE *, struct diff3_block *, int));
+static int output_diff3_edscript PARAMS((FILE *, struct diff3_block *, int const[3], int const[3], char const *, char const *, char const *));
+static int output_diff3_merge PARAMS((FILE *, FILE *, struct diff3_block *, int const[3], int const[3], char const *, char const *, char const *));
+static size_t myread PARAMS((int, char *, size_t));
+static struct diff3_block *create_diff3_block PARAMS((int, int, int, int, int, int));
+static struct diff3_block *make_3way_diff PARAMS((struct diff_block *, struct diff_block *));
+static struct diff3_block *reverse_diff3_blocklist PARAMS((struct diff3_block *));
+static struct diff3_block *using_to_diff3_block PARAMS((struct diff_block *[2], struct diff_block *[2], int, int, struct diff3_block const *));
+static struct diff_block *process_diff PARAMS((char const *, char const *, struct diff_block **));
+static void check_stdout PARAMS((void));
+static void fatal PARAMS((char const *));
+static void output_diff3 PARAMS((FILE *, struct diff3_block *, int const[3], int const[3]));
+static void perror_with_exit PARAMS((char const *));
+static void try_help PARAMS((char const *));
+static void undotlines PARAMS((FILE *, int, int, int));
+static void usage PARAMS((void));
+
+static char const diff_program[] = DIFF_PROGRAM;
+
+static struct option const longopts[] =
+{
+  {"text", 0, 0, 'a'},
+  {"show-all", 0, 0, 'A'},
+  {"ed", 0, 0, 'e'},
+  {"show-overlap", 0, 0, 'E'},
+  {"label", 1, 0, 'L'},
+  {"merge", 0, 0, 'm'},
+  {"initial-tab", 0, 0, 'T'},
+  {"overlap-only", 0, 0, 'x'},
+  {"easy-only", 0, 0, '3'},
+  {"version", 0, 0, 'v'},
+  {"help", 0, 0, 129},
+  {0, 0, 0, 0}
+};
+
+/*
+ * Main program.  Calls diff twice on two pairs of input files,
+ * combines the two diffs, and outputs them.
+ */
+int
+main (argc, argv)
+     int argc;
+     char **argv;
+{
+  int c, i;
+  int mapping[3];
+  int rev_mapping[3];
+  int incompat = 0;
+  int conflicts_found;
+  struct diff_block *thread0, *thread1, *last_block;
+  struct diff3_block *diff3;
+  int tag_count = 0;
+  char *tag_strings[3];
+  char *commonname;
+  char **file;
+  struct stat statb;
+
+  initialize_main (&argc, &argv);
+  program_name = argv[0];
+
+  while ((c = getopt_long (argc, argv, "aeimvx3AEL:TX", longopts, 0)) != EOF)
+    {
+      switch (c)
+	{
+	case 'a':
+	  always_text = 1;
+	  break;
+	case 'A':
+	  show_2nd = 1;
+	  flagging = 1;
+	  incompat++;
+	  break;
+	case 'x':
+	  overlap_only = 1;
+	  incompat++;
+	  break;
+	case '3':
+	  simple_only = 1;
+	  incompat++;
+	  break;
+	case 'i':
+	  finalwrite = 1;
+	  break;
+	case 'm':
+	  merge = 1;
+	  break;
+	case 'X':
+	  overlap_only = 1;
+	  /* Falls through */
+	case 'E':
+	  flagging = 1;
+	  /* Falls through */
+	case 'e':
+	  incompat++;
+	  break;
+	case 'T':
+	  tab_align_flag = 1;
+	  break;
+	case 'v':
+	  printf ("diff3 - GNU diffutils version %s\n", version_string);
+	  exit (0);
+	case 129:
+	  usage ();
+	  check_stdout ();
+	  exit (0);
+	case 'L':
+	  /* Handle up to three -L options.  */
+	  if (tag_count < 3)
+	    {
+	      tag_strings[tag_count++] = optarg;
+	      break;
+	    }
+	  try_help ("Too many labels were given.  The limit is 3.");
+	default:
+	  try_help (0);
+	}
+    }
+
+  edscript = incompat & ~merge;  /* -AeExX3 without -m implies ed script.  */
+  show_2nd |= ~incompat & merge;  /* -m without -AeExX3 implies -A.  */
+  flagging |= ~incompat & merge;
+
+  if (incompat > 1  /* Ensure at most one of -AeExX3.  */
+      || finalwrite & merge /* -i -m would rewrite input file.  */
+      || (tag_count && ! flagging)) /* -L requires one of -AEX.  */
+    try_help ("incompatible options");
+
+  if (argc - optind != 3)
+    try_help (argc - optind < 3 ? "missing operand" : "extra operand");
+
+  file = &argv[optind];
+
+  for (i = tag_count; i < 3; i++)
+    tag_strings[i] = file[i];
+
+  /* Always compare file1 to file2, even if file2 is "-".
+     This is needed for -mAeExX3.  Using the file0 as
+     the common file would produce wrong results, because if the
+     file0-file1 diffs didn't line up with the file0-file2 diffs
+     (which is entirely possible since we don't use diff's -n option),
+     diff3 might report phantom changes from file1 to file2.  */
+
+  if (strcmp (file[2], "-") == 0)
+    {
+      /* Sigh.  We've got standard input as the last arg.  We can't
+	 call diff twice on stdin.  Use the middle arg as the common
+	 file instead.  */
+      if (strcmp (file[0], "-") == 0 || strcmp (file[1], "-") == 0)
+	fatal ("`-' specified for more than one input file");
+      mapping[0] = 0;
+      mapping[1] = 2;
+      mapping[2] = 1;
+    }
+  else
+    {
+      /* Normal, what you'd expect */
+      mapping[0] = 0;
+      mapping[1] = 1;
+      mapping[2] = 2;
+    }
+
+  for (i = 0; i < 3; i++)
+    rev_mapping[mapping[i]] = i;
+
+  for (i = 0; i < 3; i++)
+    if (strcmp (file[i], "-") != 0)
+      {
+	if (stat (file[i], &statb) < 0)
+	  perror_with_exit (file[i]);
+	else if (S_ISDIR(statb.st_mode))
+	  {
+	    fprintf (stderr, "%s: %s: Is a directory\n",
+		     program_name, file[i]);
+	    exit (2);
+	  }
+      }
+
+#if !defined(SIGCHLD) && defined(SIGCLD)
+#define SIGCHLD SIGCLD
+#endif
+#ifdef SIGCHLD
+  /* System V fork+wait does not work if SIGCHLD is ignored.  */
+  signal (SIGCHLD, SIG_DFL);
+#endif
+
+  commonname = file[rev_mapping[FILEC]];
+  thread1 = process_diff (file[rev_mapping[FILE1]], commonname, &last_block);
+  if (thread1)
+    for (i = 0; i < 2; i++)
+      {
+	horizon_lines = max (horizon_lines, D_NUMLINES (thread1, i));
+	horizon_lines = max (horizon_lines, D_NUMLINES (last_block, i));
+      }
+  thread0 = process_diff (file[rev_mapping[FILE0]], commonname, &last_block);
+  diff3 = make_3way_diff (thread0, thread1);
+  if (edscript)
+    conflicts_found
+      = output_diff3_edscript (stdout, diff3, mapping, rev_mapping,
+			       tag_strings[0], tag_strings[1], tag_strings[2]);
+  else if (merge)
+    {
+      if (! freopen (file[rev_mapping[FILE0]], "r", stdin))
+	perror_with_exit (file[rev_mapping[FILE0]]);
+      conflicts_found
+	= output_diff3_merge (stdin, stdout, diff3, mapping, rev_mapping,
+			      tag_strings[0], tag_strings[1], tag_strings[2]);
+      if (ferror (stdin))
+	fatal ("read error");
+    }
+  else
+    {
+      output_diff3 (stdout, diff3, mapping, rev_mapping);
+      conflicts_found = 0;
+    }
+
+  check_stdout ();
+  exit (conflicts_found);
+  return conflicts_found;
+}
+
+static void
+try_help (reason)
+     char const *reason;
+{
+  if (reason)
+    fprintf (stderr, "%s: %s\n", program_name, reason);
+  fprintf (stderr, "%s: Try `%s --help' for more information.\n",
+	   program_name, program_name);
+  exit (2);
+}
+
+static void
+check_stdout ()
+{
+  if (ferror (stdout) || fclose (stdout) != 0)
+    fatal ("write error");
+}
+
+/*
+ * Explain, patiently and kindly, how to use this program.
+ */
+static void
+usage ()
+{
+  printf ("Usage: %s [OPTION]... MYFILE OLDFILE YOURFILE\n\n", program_name);
+
+  printf ("%s", "\
+  -e  --ed  Output unmerged changes from OLDFILE to YOURFILE into MYFILE.\n\
+  -E  --show-overlap  Output unmerged changes, bracketing conflicts.\n\
+  -A  --show-all  Output all changes, bracketing conflicts.\n\
+  -x  --overlap-only  Output overlapping changes.\n\
+  -X  Output overlapping changes, bracketing them.\n\
+  -3  --easy-only  Output unmerged nonoverlapping changes.\n\n");
+  printf ("%s", "\
+  -m  --merge  Output merged file instead of ed script (default -A).\n\
+  -L LABEL  --label=LABEL  Use LABEL instead of file name.\n\
+  -i  Append `w' and `q' commands to ed scripts.\n\
+  -a  --text  Treat all files as text.\n\
+  -T  --initial-tab  Make tabs line up by prepending a tab.\n\n");
+  printf ("%s", "\
+  -v  --version  Output version info.\n\
+  --help  Output this help.\n\n");
+  printf ("If a FILE is `-', read standard input.\n");
+}
+
+/*
+ * Routines that combine the two diffs together into one.  The
+ * algorithm used follows:
+ *
+ *   File2 is shared in common between the two diffs.
+ *   Diff02 is the diff between 0 and 2.
+ *   Diff12 is the diff between 1 and 2.
+ *
+ *	1) Find the range for the first block in File2.
+ *	    a) Take the lowest of the two ranges (in File2) in the two
+ *	       current blocks (one from each diff) as being the low
+ *	       water mark.  Assign the upper end of this block as
+ *	       being the high water mark and move the current block up
+ *	       one.  Mark the block just moved over as to be used.
+ *	    b) Check the next block in the diff that the high water
+ *	       mark is *not* from.
+ *
+ *	       *If* the high water mark is above
+ *	       the low end of the range in that block,
+ *
+ *		   mark that block as to be used and move the current
+ *		   block up.  Set the high water mark to the max of
+ *		   the high end of this block and the current.  Repeat b.
+ *
+ *	 2) Find the corresponding ranges in File0 (from the blocks
+ *	    in diff02; line per line outside of diffs) and in File1.
+ *	    Create a diff3_block, reserving space as indicated by the ranges.
+ *
+ *	 3) Copy all of the pointers for file2 in.  At least for now,
+ *	    do memcmp's between corresponding strings in the two diffs.
+ *
+ *	 4) Copy all of the pointers for file0 and 1 in.  Get what you
+ *	    need from file2 (when there isn't a diff block, it's
+ *	    identical to file2 within the range between diff blocks).
+ *
+ *	 5) If the diff blocks you used came from only one of the two
+ *	    strings of diffs, then that file (i.e. the one other than
+ *	    the common file in that diff) is the odd person out.  If you used
+ *	    diff blocks from both sets, check to see if files 0 and 1 match:
+ *
+ *		Same number of lines?  If so, do a set of memcmp's (if a
+ *	    memcmp matches; copy the pointer over; it'll be easier later
+ *	    if you have to do any compares).  If they match, 0 & 1 are
+ *	    the same.  If not, all three different.
+ *
+ *   Then you do it again, until you run out of blocks.
+ *
+ */
+
+/*
+ * This routine makes a three way diff (chain of diff3_block's) from two
+ * two way diffs (chains of diff_block's).  It is assumed that each of
+ * the two diffs passed are onto the same file (i.e. that each of the
+ * diffs were made "to" the same file).  The three way diff pointer
+ * returned will have numbering FILE0--the other file in diff02,
+ * FILE1--the other file in diff12, and FILEC--the common file.
+ */
+static struct diff3_block *
+make_3way_diff (thread0, thread1)
+     struct diff_block *thread0, *thread1;
+{
+/*
+ * This routine works on the two diffs passed to it as threads.
+ * Thread number 0 is diff02, thread number 1 is diff12.  The USING
+ * array is set to the base of the list of blocks to be used to
+ * construct each block of the three way diff; if no blocks from a
+ * particular thread are to be used, that element of the using array
+ * is set to 0.  The elements LAST_USING array are set to the last
+ * elements on each of the using lists.
+ *
+ * The HIGH_WATER_MARK is set to the highest line number in the common file
+ * described in any of the diffs in either of the USING lists.  The
+ * HIGH_WATER_THREAD names the thread.  Similarly the BASE_WATER_MARK
+ * and BASE_WATER_THREAD describe the lowest line number in the common file
+ * described in any of the diffs in either of the USING lists.  The
+ * HIGH_WATER_DIFF is the diff from which the HIGH_WATER_MARK was
+ * taken.
+ *
+ * The HIGH_WATER_DIFF should always be equal to LAST_USING
+ * [HIGH_WATER_THREAD].  The OTHER_DIFF is the next diff to check for
+ * higher water, and should always be equal to
+ * CURRENT[HIGH_WATER_THREAD ^ 0x1].  The OTHER_THREAD is the thread
+ * in which the OTHER_DIFF is, and hence should always be equal to
+ * HIGH_WATER_THREAD ^ 0x1.
+ *
+ * The variable LAST_DIFF is kept set to the last diff block produced
+ * by this routine, for line correspondence purposes between that diff
+ * and the one currently being worked on.  It is initialized to
+ * ZERO_DIFF before any blocks have been created.
+ */
+
+  struct diff_block
+    *using[2],
+    *last_using[2],
+    *current[2];
+
+  int
+    high_water_mark;
+
+  int
+    high_water_thread,
+    base_water_thread,
+    other_thread;
+
+  struct diff_block
+    *high_water_diff,
+    *other_diff;
+
+  struct diff3_block
+    *result,
+    *tmpblock,
+    **result_end;
+
+  struct diff3_block const *last_diff3;
+
+  static struct diff3_block const zero_diff3;
+
+  /* Initialization */
+  result = 0;
+  result_end = &result;
+  current[0] = thread0; current[1] = thread1;
+  last_diff3 = &zero_diff3;
+
+  /* Sniff up the threads until we reach the end */
+
+  while (current[0] || current[1])
+    {
+      using[0] = using[1] = last_using[0] = last_using[1] = 0;
+
+      /* Setup low and high water threads, diffs, and marks.  */
+      if (!current[0])
+	base_water_thread = 1;
+      else if (!current[1])
+	base_water_thread = 0;
+      else
+	base_water_thread =
+	  (D_LOWLINE (current[0], FC) > D_LOWLINE (current[1], FC));
+
+      high_water_thread = base_water_thread;
+
+      high_water_diff = current[high_water_thread];
+
+#if 0
+      /* low and high waters start off same diff */
+      base_water_mark = D_LOWLINE (high_water_diff, FC);
+#endif
+
+      high_water_mark = D_HIGHLINE (high_water_diff, FC);
+
+      /* Make the diff you just got info from into the using class */
+      using[high_water_thread]
+	= last_using[high_water_thread]
+	= high_water_diff;
+      current[high_water_thread] = high_water_diff->next;
+      last_using[high_water_thread]->next = 0;
+
+      /* And mark the other diff */
+      other_thread = high_water_thread ^ 0x1;
+      other_diff = current[other_thread];
+
+      /* Shuffle up the ladder, checking the other diff to see if it
+	 needs to be incorporated.  */
+      while (other_diff
+	     && D_LOWLINE (other_diff, FC) <= high_water_mark + 1)
+	{
+
+	  /* Incorporate this diff into the using list.  Note that
+	     this doesn't take it off the current list */
+	  if (using[other_thread])
+	    last_using[other_thread]->next = other_diff;
+	  else
+	    using[other_thread] = other_diff;
+	  last_using[other_thread] = other_diff;
+
+	  /* Take it off the current list.  Note that this following
+	     code assumes that other_diff enters it equal to
+	     current[high_water_thread ^ 0x1] */
+	  current[other_thread] = current[other_thread]->next;
+	  other_diff->next = 0;
+
+	  /* Set the high_water stuff
+	     If this comparison is equal, then this is the last pass
+	     through this loop; since diff blocks within a given
+	     thread cannot overlap, the high_water_mark will be
+	     *below* the range_start of either of the next diffs.  */
+
+	  if (high_water_mark < D_HIGHLINE (other_diff, FC))
+	    {
+	      high_water_thread ^= 1;
+	      high_water_diff = other_diff;
+	      high_water_mark = D_HIGHLINE (other_diff, FC);
+	    }
+
+	  /* Set the other diff */
+	  other_thread = high_water_thread ^ 0x1;
+	  other_diff = current[other_thread];
+	}
+
+      /* The using lists contain a list of all of the blocks to be
+	 included in this diff3_block.  Create it.  */
+
+      tmpblock = using_to_diff3_block (using, last_using,
+				       base_water_thread, high_water_thread,
+				       last_diff3);
+
+      if (!tmpblock)
+	fatal ("internal error: screwup in format of diff blocks");
+
+      /* Put it on the list.  */
+      *result_end = tmpblock;
+      result_end = &tmpblock->next;
+
+      /* Set up corresponding lines correctly.  */
+      last_diff3 = tmpblock;
+    }
+  return result;
+}
+
+/*
+ * using_to_diff3_block:
+ *   This routine takes two lists of blocks (from two separate diff
+ * threads) and puts them together into one diff3 block.
+ * It then returns a pointer to this diff3 block or 0 for failure.
+ *
+ * All arguments besides using are for the convenience of the routine;
+ * they could be derived from the using array.
+ * LAST_USING is a pair of pointers to the last blocks in the using
+ * structure.
+ * LOW_THREAD and HIGH_THREAD tell which threads contain the lowest
+ * and highest line numbers for File0.
+ * last_diff3 contains the last diff produced in the calling routine.
+ * This is used for lines mappings which would still be identical to
+ * the state that diff ended in.
+ *
+ * A distinction should be made in this routine between the two diffs
+ * that are part of a normal two diff block, and the three diffs that
+ * are part of a diff3_block.
+ */
+static struct diff3_block *
+using_to_diff3_block (using, last_using, low_thread, high_thread, last_diff3)
+     struct diff_block
+       *using[2],
+       *last_using[2];
+     int low_thread, high_thread;
+     struct diff3_block const *last_diff3;
+{
+  int low[2], high[2];
+  struct diff3_block *result;
+  struct diff_block *ptr;
+  int d, i;
+
+  /* Find the range in the common file.  */
+  int lowc = D_LOWLINE (using[low_thread], FC);
+  int highc = D_HIGHLINE (last_using[high_thread], FC);
+
+  /* Find the ranges in the other files.
+     If using[d] is null, that means that the file to which that diff
+     refers is equivalent to the common file over this range.  */
+
+  for (d = 0; d < 2; d++)
+    if (using[d])
+      {
+	low[d] = D_LOW_MAPLINE (using[d], FC, FO, lowc);
+	high[d] = D_HIGH_MAPLINE (last_using[d], FC, FO, highc);
+      }
+    else
+      {
+	low[d] = D_HIGH_MAPLINE (last_diff3, FILEC, FILE0 + d, lowc);
+	high[d] = D_HIGH_MAPLINE (last_diff3, FILEC, FILE0 + d, highc);
+      }
+
+  /* Create a block with the appropriate sizes */
+  result = create_diff3_block (low[0], high[0], low[1], high[1], lowc, highc);
+
+  /* Copy information for the common file.
+     Return with a zero if any of the compares failed.  */
+
+  for (d = 0; d < 2; d++)
+    for (ptr = using[d]; ptr; ptr = D_NEXT (ptr))
+      {
+	int result_offset = D_LOWLINE (ptr, FC) - lowc;
+
+	if (!copy_stringlist (D_LINEARRAY (ptr, FC),
+			      D_LENARRAY (ptr, FC),
+			      D_LINEARRAY (result, FILEC) + result_offset,
+			      D_LENARRAY (result, FILEC) + result_offset,
+			      D_NUMLINES (ptr, FC)))
+	  return 0;
+      }
+
+  /* Copy information for file d.  First deal with anything that might be
+     before the first diff.  */
+
+  for (d = 0; d < 2; d++)
+    {
+      struct diff_block *u = using[d];
+      int lo = low[d], hi = high[d];
+
+      for (i = 0;
+	   i + lo < (u ? D_LOWLINE (u, FO) : hi + 1);
+	   i++)
+	{
+	  D_RELNUM (result, FILE0 + d, i) = D_RELNUM (result, FILEC, i);
+	  D_RELLEN (result, FILE0 + d, i) = D_RELLEN (result, FILEC, i);
+	}
+
+      for (ptr = u; ptr; ptr = D_NEXT (ptr))
+	{
+	  int result_offset = D_LOWLINE (ptr, FO) - lo;
+	  int linec;
+
+	  if (!copy_stringlist (D_LINEARRAY (ptr, FO),
+				D_LENARRAY (ptr, FO),
+				D_LINEARRAY (result, FILE0 + d) + result_offset,
+				D_LENARRAY (result, FILE0 + d) + result_offset,
+				D_NUMLINES (ptr, FO)))
+	    return 0;
+
+	  /* Catch the lines between here and the next diff */
+	  linec = D_HIGHLINE (ptr, FC) + 1 - lowc;
+	  for (i = D_HIGHLINE (ptr, FO) + 1 - lo;
+	       i < (D_NEXT (ptr) ? D_LOWLINE (D_NEXT (ptr), FO) : hi + 1) - lo;
+	       i++)
+	    {
+	      D_RELNUM (result, FILE0 + d, i) = D_RELNUM (result, FILEC, linec);
+	      D_RELLEN (result, FILE0 + d, i) = D_RELLEN (result, FILEC, linec);
+	      linec++;
+	    }
+	}
+    }
+
+  /* Set correspond */
+  if (!using[0])
+    D3_TYPE (result) = DIFF_2ND;
+  else if (!using[1])
+    D3_TYPE (result) = DIFF_1ST;
+  else
+    {
+      int nl0 = D_NUMLINES (result, FILE0);
+      int nl1 = D_NUMLINES (result, FILE1);
+
+      if (nl0 != nl1
+	  || !compare_line_list (D_LINEARRAY (result, FILE0),
+				 D_LENARRAY (result, FILE0),
+				 D_LINEARRAY (result, FILE1),
+				 D_LENARRAY (result, FILE1),
+				 nl0))
+	D3_TYPE (result) = DIFF_ALL;
+      else
+	D3_TYPE (result) = DIFF_3RD;
+    }
+
+  return result;
+}
+
+/*
+ * This routine copies pointers from a list of strings to a different list
+ * of strings.  If a spot in the second list is already filled, it
+ * makes sure that it is filled with the same string; if not it
+ * returns 0, the copy incomplete.
+ * Upon successful completion of the copy, it returns 1.
+ */
+static int
+copy_stringlist (fromptrs, fromlengths, toptrs, tolengths, copynum)
+     char * const fromptrs[];
+     char *toptrs[];
+     size_t const fromlengths[];
+     size_t tolengths[];
+     int copynum;
+{
+  register char * const *f = fromptrs;
+  register char **t = toptrs;
+  register size_t const *fl = fromlengths;
+  register size_t *tl = tolengths;
+
+  while (copynum--)
+    {
+      if (*t)
+	{ if (*fl != *tl || memcmp (*f, *t, *fl)) return 0; }
+      else
+	{ *t = *f ; *tl = *fl; }
+
+      t++; f++; tl++; fl++;
+    }
+  return 1;
+}
+
+/*
+ * Create a diff3_block, with ranges as specified in the arguments.
+ * Allocate the arrays for the various pointers (and zero them) based
+ * on the arguments passed.  Return the block as a result.
+ */
+static struct diff3_block *
+create_diff3_block (low0, high0, low1, high1, low2, high2)
+     register int low0, high0, low1, high1, low2, high2;
+{
+  struct diff3_block *result = ALLOCATE (1, struct diff3_block);
+  int numlines;
+
+  D3_TYPE (result) = ERROR;
+  D_NEXT (result) = 0;
+
+  /* Assign ranges */
+  D_LOWLINE (result, FILE0) = low0;
+  D_HIGHLINE (result, FILE0) = high0;
+  D_LOWLINE (result, FILE1) = low1;
+  D_HIGHLINE (result, FILE1) = high1;
+  D_LOWLINE (result, FILE2) = low2;
+  D_HIGHLINE (result, FILE2) = high2;
+
+  /* Allocate and zero space */
+  numlines = D_NUMLINES (result, FILE0);
+  if (numlines)
+    {
+      D_LINEARRAY (result, FILE0) = ALLOCATE (numlines, char *);
+      D_LENARRAY (result, FILE0) = ALLOCATE (numlines, size_t);
+      bzero (D_LINEARRAY (result, FILE0), (numlines * sizeof (char *)));
+      bzero (D_LENARRAY (result, FILE0), (numlines * sizeof (size_t)));
+    }
+  else
+    {
+      D_LINEARRAY (result, FILE0) = 0;
+      D_LENARRAY (result, FILE0) = 0;
+    }
+
+  numlines = D_NUMLINES (result, FILE1);
+  if (numlines)
+    {
+      D_LINEARRAY (result, FILE1) = ALLOCATE (numlines, char *);
+      D_LENARRAY (result, FILE1) = ALLOCATE (numlines, size_t);
+      bzero (D_LINEARRAY (result, FILE1), (numlines * sizeof (char *)));
+      bzero (D_LENARRAY (result, FILE1), (numlines * sizeof (size_t)));
+    }
+  else
+    {
+      D_LINEARRAY (result, FILE1) = 0;
+      D_LENARRAY (result, FILE1) = 0;
+    }
+
+  numlines = D_NUMLINES (result, FILE2);
+  if (numlines)
+    {
+      D_LINEARRAY (result, FILE2) = ALLOCATE (numlines, char *);
+      D_LENARRAY (result, FILE2) = ALLOCATE (numlines, size_t);
+      bzero (D_LINEARRAY (result, FILE2), (numlines * sizeof (char *)));
+      bzero (D_LENARRAY (result, FILE2), (numlines * sizeof (size_t)));
+    }
+  else
+    {
+      D_LINEARRAY (result, FILE2) = 0;
+      D_LENARRAY (result, FILE2) = 0;
+    }
+
+  /* Return */
+  return result;
+}
+
+/*
+ * Compare two lists of lines of text.
+ * Return 1 if they are equivalent, 0 if not.
+ */
+static int
+compare_line_list (list1, lengths1, list2, lengths2, nl)
+     char * const list1[], * const list2[];
+     size_t const lengths1[], lengths2[];
+     int nl;
+{
+  char
+    * const *l1 = list1,
+    * const *l2 = list2;
+  size_t const
+    *lgths1 = lengths1,
+    *lgths2 = lengths2;
+
+  while (nl--)
+    if (!*l1 || !*l2 || *lgths1 != *lgths2++
+	|| memcmp (*l1++, *l2++, *lgths1++))
+      return 0;
+  return 1;
+}
+
+/*
+ * Routines to input and parse two way diffs.
+ */
+
+extern char **environ;
+
+static struct diff_block *
+process_diff (filea, fileb, last_block)
+     char const *filea, *fileb;
+     struct diff_block **last_block;
+{
+  char *diff_contents;
+  char *diff_limit;
+  char *scan_diff;
+  enum diff_type dt;
+  int i;
+  struct diff_block *block_list, **block_list_end, *bptr;
+
+  diff_limit = read_diff (filea, fileb, &diff_contents);
+  scan_diff = diff_contents;
+  block_list_end = &block_list;
+  bptr = 0; /* Pacify `gcc -W'.  */
+
+  while (scan_diff < diff_limit)
+    {
+      bptr = ALLOCATE (1, struct diff_block);
+      bptr->lines[0] = bptr->lines[1] = 0;
+      bptr->lengths[0] = bptr->lengths[1] = 0;
+
+      dt = process_diff_control (&scan_diff, bptr);
+      if (dt == ERROR || *scan_diff != '\n')
+	{
+	  fprintf (stderr, "%s: diff error: ", program_name);
+	  do
+	    {
+	      putc (*scan_diff, stderr);
+	    }
+	  while (*scan_diff++ != '\n');
+	  exit (2);
+	}
+      scan_diff++;
+
+      /* Force appropriate ranges to be null, if necessary */
+      switch (dt)
+	{
+	case ADD:
+	  bptr->ranges[0][0]++;
+	  break;
+	case DELETE:
+	  bptr->ranges[1][0]++;
+	  break;
+	case CHANGE:
+	  break;
+	default:
+	  fatal ("internal error: invalid diff type in process_diff");
+	  break;
+	}
+
+      /* Allocate space for the pointers for the lines from filea, and
+	 parcel them out among these pointers */
+      if (dt != ADD)
+	{
+	  int numlines = D_NUMLINES (bptr, 0);
+	  bptr->lines[0] = ALLOCATE (numlines, char *);
+	  bptr->lengths[0] = ALLOCATE (numlines, size_t);
+	  for (i = 0; i < numlines; i++)
+	    scan_diff = scan_diff_line (scan_diff,
+					&(bptr->lines[0][i]),
+					&(bptr->lengths[0][i]),
+					diff_limit,
+					'<');
+	}
+
+      /* Get past the separator for changes */
+      if (dt == CHANGE)
+	{
+	  if (strncmp (scan_diff, "---\n", 4))
+	    fatal ("invalid diff format; invalid change separator");
+	  scan_diff += 4;
+	}
+
+      /* Allocate space for the pointers for the lines from fileb, and
+	 parcel them out among these pointers */
+      if (dt != DELETE)
+	{
+	  int numlines = D_NUMLINES (bptr, 1);
+	  bptr->lines[1] = ALLOCATE (numlines, char *);
+	  bptr->lengths[1] = ALLOCATE (numlines, size_t);
+	  for (i = 0; i < numlines; i++)
+	    scan_diff = scan_diff_line (scan_diff,
+					&(bptr->lines[1][i]),
+					&(bptr->lengths[1][i]),
+					diff_limit,
+					'>');
+	}
+
+      /* Place this block on the blocklist.  */
+      *block_list_end = bptr;
+      block_list_end = &bptr->next;
+    }
+
+  *block_list_end = 0;
+  *last_block = bptr;
+  return block_list;
+}
+
+/*
+ * This routine will parse a normal format diff control string.  It
+ * returns the type of the diff (ERROR if the format is bad).  All of
+ * the other important information is filled into to the structure
+ * pointed to by db, and the string pointer (whose location is passed
+ * to this routine) is updated to point beyond the end of the string
+ * parsed.  Note that only the ranges in the diff_block will be set by
+ * this routine.
+ *
+ * If some specific pair of numbers has been reduced to a single
+ * number, then both corresponding numbers in the diff block are set
+ * to that number.  In general these numbers are interpetted as ranges
+ * inclusive, unless being used by the ADD or DELETE commands.  It is
+ * assumed that these will be special cased in a superior routine.
+ */
+
+static enum diff_type
+process_diff_control (string, db)
+     char **string;
+     struct diff_block *db;
+{
+  char *s = *string;
+  int holdnum;
+  enum diff_type type;
+
+/* These macros are defined here because they can use variables
+   defined in this function.  Don't try this at home kids, we're
+   trained professionals!
+
+   Also note that SKIPWHITE only recognizes tabs and spaces, and
+   that READNUM can only read positive, integral numbers */
+
+#define	SKIPWHITE(s)	{ while (*s == ' ' || *s == '\t') s++; }
+#define	READNUM(s, num)	\
+	{ unsigned char c = *s; if (!ISDIGIT (c)) return ERROR; holdnum = 0; \
+	  do { holdnum = (c - '0' + holdnum * 10); }	\
+	  while (ISDIGIT (c = *++s)); (num) = holdnum; }
+
+  /* Read first set of digits */
+  SKIPWHITE (s);
+  READNUM (s, db->ranges[0][START]);
+
+  /* Was that the only digit? */
+  SKIPWHITE (s);
+  if (*s == ',')
+    {
+      /* Get the next digit */
+      s++;
+      READNUM (s, db->ranges[0][END]);
+    }
+  else
+    db->ranges[0][END] = db->ranges[0][START];
+
+  /* Get the letter */
+  SKIPWHITE (s);
+  switch (*s)
+    {
+    case 'a':
+      type = ADD;
+      break;
+    case 'c':
+      type = CHANGE;
+      break;
+    case 'd':
+      type = DELETE;
+      break;
+    default:
+      return ERROR;			/* Bad format */
+    }
+  s++;				/* Past letter */
+
+  /* Read second set of digits */
+  SKIPWHITE (s);
+  READNUM (s, db->ranges[1][START]);
+
+  /* Was that the only digit? */
+  SKIPWHITE (s);
+  if (*s == ',')
+    {
+      /* Get the next digit */
+      s++;
+      READNUM (s, db->ranges[1][END]);
+      SKIPWHITE (s);		/* To move to end */
+    }
+  else
+    db->ranges[1][END] = db->ranges[1][START];
+
+  *string = s;
+  return type;
+}
+
+static char *
+read_diff (filea, fileb, output_placement)
+     char const *filea, *fileb;
+     char **output_placement;
+{
+  char *diff_result;
+  size_t bytes, current_chunk_size, total;
+  int fd, wstatus;
+  struct stat pipestat;
+
+  /* 302 / 1000 is log10(2.0) rounded up.  Subtract 1 for the sign bit;
+     add 1 for integer division truncation; add 1 more for a minus sign.  */
+#define INT_STRLEN_BOUND(type) ((sizeof(type)*CHAR_BIT - 1) * 302 / 1000 + 2)
+
+#if HAVE_FORK
+
+  char const *argv[7];
+  char horizon_arg[17 + INT_STRLEN_BOUND (int)];
+  char const **ap;
+  int fds[2];
+  pid_t pid;
+
+  ap = argv;
+  *ap++ = diff_program;
+  if (always_text)
+    *ap++ = "-a";
+  sprintf (horizon_arg, "--horizon-lines=%d", horizon_lines);
+  *ap++ = horizon_arg;
+  *ap++ = "--";
+  *ap++ = filea;
+  *ap++ = fileb;
+  *ap = 0;
+
+  if (pipe (fds) != 0)
+    perror_with_exit ("pipe");
+
+  pid = vfork ();
+  if (pid == 0)
+    {
+      /* Child */
+      close (fds[0]);
+      if (fds[1] != STDOUT_FILENO)
+	{
+	  dup2 (fds[1], STDOUT_FILENO);
+	  close (fds[1]);
+	}
+      execve (diff_program, (char **) argv, environ);
+      /* Avoid stdio, because the parent process's buffers are inherited.  */
+      write (STDERR_FILENO, diff_program, strlen (diff_program));
+      write (STDERR_FILENO, ": not found\n", 12);
+      _exit (2);
+    }
+
+  if (pid == -1)
+    perror_with_exit ("fork failed");
+
+  close (fds[1]);		/* Prevent erroneous lack of EOF */
+  fd = fds[0];
+
+#else /* ! HAVE_FORK */
+
+  FILE *fpipe;
+  char *command = xmalloc (sizeof (diff_program) + 30 + INT_STRLEN_BOUND (int)
+			   + 4 * (strlen (filea) + strlen (fileb)));
+  char *p;
+  sprintf (command, "%s -a --horizon-lines=%d -- ",
+	   diff_program, horizon_lines);
+  p = command + strlen (command);
+  SYSTEM_QUOTE_ARG (p, filea);
+  *p++ = ' ';
+  SYSTEM_QUOTE_ARG (p, fileb);
+  *p = '\0';
+  fpipe = popen (command, "r");
+  if (!fpipe)
+    perror_with_exit (command);
+  free (command);
+  fd = fileno (fpipe);
+
+#endif /* ! HAVE_FORK */
+
+  current_chunk_size = 8 * 1024;
+  if (fstat (fd, &pipestat) == 0)
+    current_chunk_size = max (current_chunk_size, STAT_BLOCKSIZE (pipestat));
+
+  diff_result = xmalloc (current_chunk_size);
+  total = 0;
+  do {
+    bytes = myread (fd,
+		    diff_result + total,
+		    current_chunk_size - total);
+    total += bytes;
+    if (total == current_chunk_size)
+      {
+	if (current_chunk_size < 2 * current_chunk_size)
+	  current_chunk_size = 2 * current_chunk_size;
+	else if (current_chunk_size < (size_t) -1)
+	  current_chunk_size = (size_t) -1;
+	else
+	  fatal ("files are too large to fit into memory");
+	diff_result = xrealloc (diff_result, (current_chunk_size *= 2));
+      }
+  } while (bytes);
+
+  if (total != 0 && diff_result[total-1] != '\n')
+    fatal ("invalid diff format; incomplete last line");
+
+  *output_placement = diff_result;
+
+#if ! HAVE_FORK
+
+  wstatus = pclose (fpipe);
+
+#else /* HAVE_FORK */
+
+  if (close (fd) != 0)
+    perror_with_exit ("pipe close");
+  if (waitpid (pid, &wstatus, 0) < 0)
+    perror_with_exit ("waitpid failed");
+
+#endif /* HAVE_FORK */
+
+  if (! (WIFEXITED (wstatus) && WEXITSTATUS (wstatus) < 2))
+    fatal ("subsidiary diff failed");
+
+  return diff_result + total;
+}
+
+
+/*
+ * Scan a regular diff line (consisting of > or <, followed by a
+ * space, followed by text (including nulls) up to a newline.
+ *
+ * This next routine began life as a macro and many parameters in it
+ * are used as call-by-reference values.
+ */
+static char *
+scan_diff_line (scan_ptr, set_start, set_length, limit, leadingchar)
+     char *scan_ptr, **set_start;
+     size_t *set_length;
+     char *limit;
+     int leadingchar;
+{
+  char *line_ptr;
+
+  if (!(scan_ptr[0] == leadingchar
+	&& scan_ptr[1] == ' '))
+    fatal ("invalid diff format; incorrect leading line chars");
+
+  *set_start = line_ptr = scan_ptr + 2;
+  while (*line_ptr++ != '\n')
+    ;
+
+  /* Include newline if the original line ended in a newline,
+     or if an edit script is being generated.
+     Copy any missing newline message to stderr if an edit script is being
+     generated, because edit scripts cannot handle missing newlines.
+     Return the beginning of the next line.  */
+  *set_length = line_ptr - *set_start;
+  if (line_ptr < limit && *line_ptr == '\\')
+    {
+      if (edscript)
+	fprintf (stderr, "%s:", program_name);
+      else
+	--*set_length;
+      line_ptr++;
+      do
+	{
+	  if (edscript)
+	    putc (*line_ptr, stderr);
+	}
+      while (*line_ptr++ != '\n');
+    }
+
+  return line_ptr;
+}
+
+/*
+ * This routine outputs a three way diff passed as a list of
+ * diff3_block's.
+ * The argument MAPPING is indexed by external file number (in the
+ * argument list) and contains the internal file number (from the
+ * diff passed).  This is important because the user expects his
+ * outputs in terms of the argument list number, and the diff passed
+ * may have been done slightly differently (if the last argument
+ * was "-", for example).
+ * REV_MAPPING is the inverse of MAPPING.
+ */
+static void
+output_diff3 (outputfile, diff, mapping, rev_mapping)
+     FILE *outputfile;
+     struct diff3_block *diff;
+     int const mapping[3], rev_mapping[3];
+{
+  int i;
+  int oddoneout;
+  char *cp;
+  struct diff3_block *ptr;
+  int line;
+  size_t length;
+  int dontprint;
+  static int skew_increment[3] = { 2, 3, 1 }; /* 0==>2==>1==>3 */
+  char const *line_prefix = tab_align_flag ? "\t" : "  ";
+
+  for (ptr = diff; ptr; ptr = D_NEXT (ptr))
+    {
+      char x[2];
+
+      switch (ptr->correspond)
+	{
+	case DIFF_ALL:
+	  x[0] = '\0';
+	  dontprint = 3;	/* Print them all */
+	  oddoneout = 3;	/* Nobody's odder than anyone else */
+	  break;
+	case DIFF_1ST:
+	case DIFF_2ND:
+	case DIFF_3RD:
+	  oddoneout = rev_mapping[(int) ptr->correspond - (int) DIFF_1ST];
+
+	  x[0] = oddoneout + '1';
+	  x[1] = '\0';
+	  dontprint = oddoneout==0;
+	  break;
+	default:
+	  fatal ("internal error: invalid diff type passed to output");
+	}
+      fprintf (outputfile, "====%s\n", x);
+
+      /* Go 0, 2, 1 if the first and third outputs are equivalent.  */
+      for (i = 0; i < 3;
+	   i = (oddoneout == 1 ? skew_increment[i] : i + 1))
+	{
+	  int realfile = mapping[i];
+	  int
+	    lowt = D_LOWLINE (ptr, realfile),
+	    hight = D_HIGHLINE (ptr, realfile);
+
+	  fprintf (outputfile, "%d:", i + 1);
+	  switch (lowt - hight)
+	    {
+	    case 1:
+	      fprintf (outputfile, "%da\n", lowt - 1);
+	      break;
+	    case 0:
+	      fprintf (outputfile, "%dc\n", lowt);
+	      break;
+	    default:
+	      fprintf (outputfile, "%d,%dc\n", lowt, hight);
+	      break;
+	    }
+
+	  if (i == dontprint) continue;
+
+	  if (lowt <= hight)
+	    {
+	      line = 0;
+	      do
+		{
+		  fprintf (outputfile, line_prefix);
+		  cp = D_RELNUM (ptr, realfile, line);
+		  length = D_RELLEN (ptr, realfile, line);
+		  fwrite (cp, sizeof (char), length, outputfile);
+		}
+	      while (++line < hight - lowt + 1);
+	      if (cp[length - 1] != '\n')
+		fprintf (outputfile, "\n\\ No newline at end of file\n");
+	    }
+	}
+    }
+}
+
+
+/*
+ * Output to OUTPUTFILE the lines of B taken from FILENUM.
+ * Double any initial '.'s; yield nonzero if any initial '.'s were doubled.
+ */
+static int
+dotlines (outputfile, b, filenum)
+     FILE *outputfile;
+     struct diff3_block *b;
+     int filenum;
+{
+  int i;
+  int leading_dot = 0;
+
+  for (i = 0;
+       i < D_NUMLINES (b, filenum);
+       i++)
+    {
+      char *line = D_RELNUM (b, filenum, i);
+      if (line[0] == '.')
+	{
+	  leading_dot = 1;
+	  fprintf (outputfile, ".");
+	}
+      fwrite (line, sizeof (char),
+	      D_RELLEN (b, filenum, i), outputfile);
+    }
+
+  return leading_dot;
+}
+
+/*
+ * Output to OUTPUTFILE a '.' line.  If LEADING_DOT is nonzero,
+ * also output a command that removes initial '.'s
+ * starting with line START and continuing for NUM lines.
+ */
+static void
+undotlines (outputfile, leading_dot, start, num)
+     FILE *outputfile;
+     int leading_dot, start, num;
+{
+  fprintf (outputfile, ".\n");
+  if (leading_dot)
+    if (num == 1)
+      fprintf (outputfile, "%ds/^\\.//\n", start);
+    else
+      fprintf (outputfile, "%d,%ds/^\\.//\n", start, start + num - 1);
+}
+
+/*
+ * This routine outputs a diff3 set of blocks as an ed script.  This
+ * script applies the changes between file's 2 & 3 to file 1.  It
+ * takes the precise format of the ed script to be output from global
+ * variables set during options processing.  Note that it does
+ * destructive things to the set of diff3 blocks it is passed; it
+ * reverses their order (this gets around the problems involved with
+ * changing line numbers in an ed script).
+ *
+ * Note that this routine has the same problem of mapping as the last
+ * one did; the variable MAPPING maps from file number according to
+ * the argument list to file number according to the diff passed.  All
+ * files listed below are in terms of the argument list.
+ * REV_MAPPING is the inverse of MAPPING.
+ *
+ * The arguments FILE0, FILE1 and FILE2 are the strings to print
+ * as the names of the three files.  These may be the actual names,
+ * or may be the arguments specified with -L.
+ *
+ * Returns 1 if conflicts were found.
+ */
+
+static int
+output_diff3_edscript (outputfile, diff, mapping, rev_mapping,
+		       file0, file1, file2)
+     FILE *outputfile;
+     struct diff3_block *diff;
+     int const mapping[3], rev_mapping[3];
+     char const *file0, *file1, *file2;
+{
+  int leading_dot;
+  int conflicts_found = 0, conflict;
+  struct diff3_block *b;
+
+  for (b = reverse_diff3_blocklist (diff); b; b = b->next)
+    {
+      /* Must do mapping correctly.  */
+      enum diff_type type
+	= ((b->correspond == DIFF_ALL) ?
+	   DIFF_ALL :
+	   ((enum diff_type)
+	    (((int) DIFF_1ST)
+	     + rev_mapping[(int) b->correspond - (int) DIFF_1ST])));
+
+      /* If we aren't supposed to do this output block, skip it.  */
+      switch (type)
+	{
+	default: continue;
+	case DIFF_2ND: if (!show_2nd) continue; conflict = 1; break;
+	case DIFF_3RD: if (overlap_only) continue; conflict = 0; break;
+	case DIFF_ALL: if (simple_only) continue; conflict = flagging; break;
+	}
+
+      if (conflict)
+	{
+	  conflicts_found = 1;
+
+
+	  /* Mark end of conflict.  */
+
+	  fprintf (outputfile, "%da\n", D_HIGHLINE (b, mapping[FILE0]));
+	  leading_dot = 0;
+	  if (type == DIFF_ALL)
+	    {
+	      if (show_2nd)
+		{
+		  /* Append lines from FILE1.  */
+		  fprintf (outputfile, "||||||| %s\n", file1);
+		  leading_dot = dotlines (outputfile, b, mapping[FILE1]);
+		}
+	      /* Append lines from FILE2.  */
+	      fprintf (outputfile, "=======\n");
+	      leading_dot |= dotlines (outputfile, b, mapping[FILE2]);
+	    }
+	  fprintf (outputfile, ">>>>>>> %s\n", file2);
+	  undotlines (outputfile, leading_dot,
+		      D_HIGHLINE (b, mapping[FILE0]) + 2,
+		      (D_NUMLINES (b, mapping[FILE1])
+		       + D_NUMLINES (b, mapping[FILE2]) + 1));
+
+
+	  /* Mark start of conflict.  */
+
+	  fprintf (outputfile, "%da\n<<<<<<< %s\n",
+		   D_LOWLINE (b, mapping[FILE0]) - 1,
+		   type == DIFF_ALL ? file0 : file1);
+	  leading_dot = 0;
+	  if (type == DIFF_2ND)
+	    {
+	      /* Prepend lines from FILE1.  */
+	      leading_dot = dotlines (outputfile, b, mapping[FILE1]);
+	      fprintf (outputfile, "=======\n");
+	    }
+	  undotlines (outputfile, leading_dot,
+		      D_LOWLINE (b, mapping[FILE0]) + 1,
+		      D_NUMLINES (b, mapping[FILE1]));
+	}
+      else if (D_NUMLINES (b, mapping[FILE2]) == 0)
+	/* Write out a delete */
+	{
+	  if (D_NUMLINES (b, mapping[FILE0]) == 1)
+	    fprintf (outputfile, "%dd\n",
+		     D_LOWLINE (b, mapping[FILE0]));
+	  else
+	    fprintf (outputfile, "%d,%dd\n",
+		     D_LOWLINE (b, mapping[FILE0]),
+		     D_HIGHLINE (b, mapping[FILE0]));
+	}
+      else
+	/* Write out an add or change */
+	{
+	  switch (D_NUMLINES (b, mapping[FILE0]))
+	    {
+	    case 0:
+	      fprintf (outputfile, "%da\n",
+		       D_HIGHLINE (b, mapping[FILE0]));
+	      break;
+	    case 1:
+	      fprintf (outputfile, "%dc\n",
+		       D_HIGHLINE (b, mapping[FILE0]));
+	      break;
+	    default:
+	      fprintf (outputfile, "%d,%dc\n",
+		       D_LOWLINE (b, mapping[FILE0]),
+		       D_HIGHLINE (b, mapping[FILE0]));
+	      break;
+	    }
+
+	  undotlines (outputfile, dotlines (outputfile, b, mapping[FILE2]),
+		      D_LOWLINE (b, mapping[FILE0]),
+		      D_NUMLINES (b, mapping[FILE2]));
+	}
+    }
+  if (finalwrite) fprintf (outputfile, "w\nq\n");
+  return conflicts_found;
+}
+
+/*
+ * Read from INFILE and output to OUTPUTFILE a set of diff3_ blocks DIFF
+ * as a merged file.  This acts like 'ed file0 <[output_diff3_edscript]',
+ * except that it works even for binary data or incomplete lines.
+ *
+ * As before, MAPPING maps from arg list file number to diff file number,
+ * REV_MAPPING is its inverse,
+ * and FILE0, FILE1, and FILE2 are the names of the files.
+ *
+ * Returns 1 if conflicts were found.
+ */
+
+static int
+output_diff3_merge (infile, outputfile, diff, mapping, rev_mapping,
+		    file0, file1, file2)
+     FILE *infile, *outputfile;
+     struct diff3_block *diff;
+     int const mapping[3], rev_mapping[3];
+     char const *file0, *file1, *file2;
+{
+  int c, i;
+  int conflicts_found = 0, conflict;
+  struct diff3_block *b;
+  int linesread = 0;
+
+  for (b = diff; b; b = b->next)
+    {
+      /* Must do mapping correctly.  */
+      enum diff_type type
+	= ((b->correspond == DIFF_ALL) ?
+	   DIFF_ALL :
+	   ((enum diff_type)
+	    (((int) DIFF_1ST)
+	     + rev_mapping[(int) b->correspond - (int) DIFF_1ST])));
+      char const *format_2nd = "<<<<<<< %s\n";
+
+      /* If we aren't supposed to do this output block, skip it.  */
+      switch (type)
+	{
+	default: continue;
+	case DIFF_2ND: if (!show_2nd) continue; conflict = 1; break;
+	case DIFF_3RD: if (overlap_only) continue; conflict = 0; break;
+	case DIFF_ALL: if (simple_only) continue; conflict = flagging;
+	  format_2nd = "||||||| %s\n";
+	  break;
+	}
+
+      /* Copy I lines from file 0.  */
+      i = D_LOWLINE (b, FILE0) - linesread - 1;
+      linesread += i;
+      while (0 <= --i)
+	do
+	  {
+	    c = getc (infile);
+	    if (c == EOF)
+	      if (ferror (infile))
+		perror_with_exit ("input file");
+	      else if (feof (infile))
+		fatal ("input file shrank");
+	    putc (c, outputfile);
+	  }
+	while (c != '\n');
+
+      if (conflict)
+	{
+	  conflicts_found = 1;
+
+	  if (type == DIFF_ALL)
+	    {
+	      /* Put in lines from FILE0 with bracket.  */
+	      fprintf (outputfile, "<<<<<<< %s\n", file0);
+	      for (i = 0;
+		   i < D_NUMLINES (b, mapping[FILE0]);
+		   i++)
+		fwrite (D_RELNUM (b, mapping[FILE0], i), sizeof (char),
+			D_RELLEN (b, mapping[FILE0], i), outputfile);
+	    }
+
+	  if (show_2nd)
+	    {
+	      /* Put in lines from FILE1 with bracket.  */
+	      fprintf (outputfile, format_2nd, file1);
+	      for (i = 0;
+		   i < D_NUMLINES (b, mapping[FILE1]);
+		   i++)
+		fwrite (D_RELNUM (b, mapping[FILE1], i), sizeof (char),
+			D_RELLEN (b, mapping[FILE1], i), outputfile);
+	    }
+
+	  fprintf (outputfile, "=======\n");
+	}
+
+      /* Put in lines from FILE2.  */
+      for (i = 0;
+	   i < D_NUMLINES (b, mapping[FILE2]);
+	   i++)
+	fwrite (D_RELNUM (b, mapping[FILE2], i), sizeof (char),
+		D_RELLEN (b, mapping[FILE2], i), outputfile);
+
+      if (conflict)
+	fprintf (outputfile, ">>>>>>> %s\n", file2);
+
+      /* Skip I lines in file 0.  */
+      i = D_NUMLINES (b, FILE0);
+      linesread += i;
+      while (0 <= --i)
+	while ((c = getc (infile)) != '\n')
+	  if (c == EOF)
+	    if (ferror (infile))
+	      perror_with_exit ("input file");
+	    else if (feof (infile))
+	      {
+		if (i || b->next)
+		  fatal ("input file shrank");
+		return conflicts_found;
+	      }
+    }
+  /* Copy rest of common file.  */
+  while ((c = getc (infile)) != EOF || !(ferror (infile) | feof (infile)))
+    putc (c, outputfile);
+  return conflicts_found;
+}
+
+/*
+ * Reverse the order of the list of diff3 blocks.
+ */
+static struct diff3_block *
+reverse_diff3_blocklist (diff)
+     struct diff3_block *diff;
+{
+  register struct diff3_block *tmp, *next, *prev;
+
+  for (tmp = diff, prev = 0;  tmp;  tmp = next)
+    {
+      next = tmp->next;
+      tmp->next = prev;
+      prev = tmp;
+    }
+
+  return prev;
+}
+
+static size_t
+myread (fd, ptr, size)
+     int fd;
+     char *ptr;
+     size_t size;
+{
+  size_t result = read (fd, ptr, size);
+  if (result == -1)
+    perror_with_exit ("read failed");
+  return result;
+}
+
+static VOID *
+xmalloc (size)
+     size_t size;
+{
+  VOID *result = (VOID *) malloc (size ? size : 1);
+  if (!result)
+    fatal ("memory exhausted");
+  return result;
+}
+
+static VOID *
+xrealloc (ptr, size)
+     VOID *ptr;
+     size_t size;
+{
+  VOID *result = (VOID *) realloc (ptr, size ? size : 1);
+  if (!result)
+    fatal ("memory exhausted");
+  return result;
+}
+
+static void
+fatal (string)
+     char const *string;
+{
+  fprintf (stderr, "%s: %s\n", program_name, string);
+  exit (2);
+}
+
+static void
+perror_with_exit (string)
+     char const *string;
+{
+  int e = errno;
+  fprintf (stderr, "%s: ", program_name);
+  errno = e;
+  perror (string);
+  exit (2);
+}
diff --git a/gnu/usr.bin/diff/dir.c b/gnu/usr.bin/diff/dir.c
new file mode 100644
index 00000000000..036a86f1128
--- /dev/null
+++ b/gnu/usr.bin/diff/dir.c
@@ -0,0 +1,216 @@
+/* Read, sort and compare two directories.  Used for GNU DIFF.
+   Copyright (C) 1988, 1989, 1992, 1993, 1994 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "diff.h"
+
+/* Read the directory named by DIR and store into DIRDATA a sorted vector
+   of filenames for its contents.  DIR->desc == -1 means this directory is
+   known to be nonexistent, so set DIRDATA to an empty vector.
+   Return -1 (setting errno) if error, 0 otherwise.  */
+
+struct dirdata
+{
+  char const **names;	/* Sorted names of files in dir, 0-terminated.  */
+  char *data;	/* Allocated storage for file names.  */
+};
+
+static int compare_names PARAMS((void const *, void const *));
+static int dir_sort PARAMS((struct file_data const *, struct dirdata *));
+
+static int
+dir_sort (dir, dirdata)
+     struct file_data const *dir;
+     struct dirdata *dirdata;
+{
+  register struct dirent *next;
+  register int i;
+
+  /* Address of block containing the files that are described.  */
+  char const **names;
+
+  /* Number of files in directory.  */
+  size_t nnames;
+
+  /* Allocated and used storage for file name data.  */
+  char *data;
+  size_t data_alloc, data_used;
+
+  dirdata->names = 0;
+  dirdata->data = 0;
+  nnames = 0;
+  data = 0;
+
+  if (dir->desc != -1)
+    {
+      /* Open the directory and check for errors.  */
+      register DIR *reading = opendir (dir->name);
+      if (!reading)
+	return -1;
+
+      /* Initialize the table of filenames.  */
+
+      data_alloc = max (1, (size_t) dir->stat.st_size);
+      data_used = 0;
+      dirdata->data = data = xmalloc (data_alloc);
+
+      /* Read the directory entries, and insert the subfiles
+	 into the `data' table.  */
+
+      while ((errno = 0, (next = readdir (reading)) != 0))
+	{
+	  char *d_name = next->d_name;
+	  size_t d_size = NAMLEN (next) + 1;
+
+	  /* Ignore the files `.' and `..' */
+	  if (d_name[0] == '.'
+	      && (d_name[1] == 0 || (d_name[1] == '.' && d_name[2] == 0)))
+	    continue;
+
+	  if (excluded_filename (d_name))
+	    continue;
+
+	  while (data_alloc < data_used + d_size)
+	    dirdata->data = data = xrealloc (data, data_alloc *= 2);
+	  memcpy (data + data_used, d_name, d_size);
+	  data_used += d_size;
+	  nnames++;
+	}
+      if (errno)
+	{
+	  int e = errno;
+	  closedir (reading);
+	  errno = e;
+	  return -1;
+	}
+#if CLOSEDIR_VOID
+      closedir (reading);
+#else
+      if (closedir (reading) != 0)
+	return -1;
+#endif
+    }
+
+  /* Create the `names' table from the `data' table.  */
+  dirdata->names = names = (char const **) xmalloc (sizeof (char *)
+						    * (nnames + 1));
+  for (i = 0;  i < nnames;  i++)
+    {
+      names[i] = data;
+      data += strlen (data) + 1;
+    }
+  names[nnames] = 0;
+
+  /* Sort the table.  */
+  qsort (names, nnames, sizeof (char *), compare_names);
+
+  return 0;
+}
+
+/* Sort the files now in the table.  */
+
+static int
+compare_names (file1, file2)
+     void const *file1, *file2;
+{
+  return filename_cmp (* (char const *const *) file1,
+		       * (char const *const *) file2);
+}
+
+/* Compare the contents of two directories named in FILEVEC[0] and FILEVEC[1].
+   This is a top-level routine; it does everything necessary for diff
+   on two directories.
+
+   FILEVEC[0].desc == -1 says directory FILEVEC[0] doesn't exist,
+   but pretend it is empty.  Likewise for FILEVEC[1].
+
+   HANDLE_FILE is a caller-provided subroutine called to handle each file.
+   It gets five operands: dir and name (rel to original working dir) of file
+   in dir 0, dir and name pathname of file in dir 1, and the recursion depth.
+
+   For a file that appears in only one of the dirs, one of the name-args
+   to HANDLE_FILE is zero.
+
+   DEPTH is the current depth in recursion, used for skipping top-level
+   files by the -S option.
+
+   Returns the maximum of all the values returned by HANDLE_FILE,
+   or 2 if trouble is encountered in opening files.  */
+
+int
+diff_dirs (filevec, handle_file, depth)
+     struct file_data const filevec[];
+     int (*handle_file) PARAMS((char const *, char const *, char const *, char const *, int));
+     int depth;
+{
+  struct dirdata dirdata[2];
+  int val = 0;			/* Return value.  */
+  int i;
+
+  /* Get sorted contents of both dirs.  */
+  for (i = 0; i < 2; i++)
+    if (dir_sort (&filevec[i], &dirdata[i]) != 0)
+      {
+	perror_with_name (filevec[i].name);
+	val = 2;
+      }
+
+  if (val == 0)
+    {
+      register char const * const *names0 = dirdata[0].names;
+      register char const * const *names1 = dirdata[1].names;
+      char const *name0 = filevec[0].name;
+      char const *name1 = filevec[1].name;
+
+      /* If `-S name' was given, and this is the topmost level of comparison,
+	 ignore all file names less than the specified starting name.  */
+
+      if (dir_start_file && depth == 0)
+	{
+	  while (*names0 && filename_cmp (*names0, dir_start_file) < 0)
+	    names0++;
+	  while (*names1 && filename_cmp (*names1, dir_start_file) < 0)
+	    names1++;
+	}
+
+      /* Loop while files remain in one or both dirs.  */
+      while (*names0 || *names1)
+	{
+	  /* Compare next name in dir 0 with next name in dir 1.
+	     At the end of a dir,
+	     pretend the "next name" in that dir is very large.  */
+	  int nameorder = (!*names0 ? 1 : !*names1 ? -1
+			   : filename_cmp (*names0, *names1));
+	  int v1 = (*handle_file) (name0, 0 < nameorder ? 0 : *names0++,
+				   name1, nameorder < 0 ? 0 : *names1++,
+				   depth + 1);
+	  if (v1 > val)
+	    val = v1;
+	}
+    }
+
+  for (i = 0; i < 2; i++)
+    {
+      if (dirdata[i].names)
+	free (dirdata[i].names);
+      if (dirdata[i].data)
+	free (dirdata[i].data);
+    }
+
+  return val;
+}
diff --git a/gnu/usr.bin/diff/ed.c b/gnu/usr.bin/diff/ed.c
new file mode 100644
index 00000000000..717ef358d0e
--- /dev/null
+++ b/gnu/usr.bin/diff/ed.c
@@ -0,0 +1,200 @@
+/* Output routines for ed-script format.
+   Copyright (C) 1988, 89, 91, 92, 93 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "diff.h"
+
+static void print_ed_hunk PARAMS((struct change *));
+static void print_rcs_hunk PARAMS((struct change *));
+static void pr_forward_ed_hunk PARAMS((struct change *));
+
+/* Print our script as ed commands.  */
+
+void
+print_ed_script (script)
+    struct change *script;
+{
+  print_script (script, find_reverse_change, print_ed_hunk);
+}
+
+/* Print a hunk of an ed diff */
+
+static void
+print_ed_hunk (hunk)
+     struct change *hunk; 
+{
+  int f0, l0, f1, l1;
+  int deletes, inserts;
+
+#if 0
+  hunk = flip_script (hunk);
+#endif
+#ifdef DEBUG
+  debug_script (hunk);
+#endif
+
+  /* Determine range of line numbers involved in each file.  */
+  analyze_hunk (hunk, &f0, &l0, &f1, &l1, &deletes, &inserts);
+  if (!deletes && !inserts)
+    return;
+
+  begin_output ();
+
+  /* Print out the line number header for this hunk */
+  print_number_range (',', &files[0], f0, l0);
+  fprintf (outfile, "%c\n", change_letter (inserts, deletes));
+
+  /* Print new/changed lines from second file, if needed */
+  if (inserts)
+    {
+      int i;
+      int inserting = 1;
+      for (i = f1; i <= l1; i++)
+	{
+	  /* Resume the insert, if we stopped.  */
+	  if (! inserting)
+	    fprintf (outfile, "%da\n",
+		     i - f1 + translate_line_number (&files[0], f0) - 1);
+	  inserting = 1;
+
+	  /* If the file's line is just a dot, it would confuse `ed'.
+	     So output it with a double dot, and set the flag LEADING_DOT
+	     so that we will output another ed-command later
+	     to change the double dot into a single dot.  */
+
+	  if (files[1].linbuf[i][0] == '.'
+	      && files[1].linbuf[i][1] == '\n')
+	    {
+	      fprintf (outfile, "..\n");
+	      fprintf (outfile, ".\n");
+	      /* Now change that double dot to the desired single dot.  */
+	      fprintf (outfile, "%ds/^\\.\\././\n",
+		       i - f1 + translate_line_number (&files[0], f0));
+	      inserting = 0;
+	    }
+	  else
+	    /* Line is not `.', so output it unmodified.  */
+	    print_1_line ("", &files[1].linbuf[i]);
+	}
+
+      /* End insert mode, if we are still in it.  */
+      if (inserting)
+	fprintf (outfile, ".\n");
+    }
+}
+
+/* Print change script in the style of ed commands,
+   but print the changes in the order they appear in the input files,
+   which means that the commands are not truly useful with ed.  */
+
+void
+pr_forward_ed_script (script)
+     struct change *script;
+{
+  print_script (script, find_change, pr_forward_ed_hunk);
+}
+
+static void
+pr_forward_ed_hunk (hunk)
+     struct change *hunk;
+{
+  int i;
+  int f0, l0, f1, l1;
+  int deletes, inserts;
+
+  /* Determine range of line numbers involved in each file.  */
+  analyze_hunk (hunk, &f0, &l0, &f1, &l1, &deletes, &inserts);
+  if (!deletes && !inserts)
+    return;
+
+  begin_output ();
+
+  fprintf (outfile, "%c", change_letter (inserts, deletes));
+  print_number_range (' ', files, f0, l0);
+  fprintf (outfile, "\n");
+
+  /* If deletion only, print just the number range.  */
+
+  if (!inserts)
+    return;
+
+  /* For insertion (with or without deletion), print the number range
+     and the lines from file 2.  */
+
+  for (i = f1; i <= l1; i++)
+    print_1_line ("", &files[1].linbuf[i]);
+
+  fprintf (outfile, ".\n");
+}
+
+/* Print in a format somewhat like ed commands
+   except that each insert command states the number of lines it inserts.
+   This format is used for RCS.  */
+
+void
+print_rcs_script (script)
+     struct change *script;
+{
+  print_script (script, find_change, print_rcs_hunk);
+}
+
+/* Print a hunk of an RCS diff */
+
+static void
+print_rcs_hunk (hunk)
+     struct change *hunk;
+{
+  int i;
+  int f0, l0, f1, l1;
+  int deletes, inserts;
+  int tf0, tl0, tf1, tl1;
+
+  /* Determine range of line numbers involved in each file.  */
+  analyze_hunk (hunk, &f0, &l0, &f1, &l1, &deletes, &inserts);
+  if (!deletes && !inserts)
+    return;
+
+  begin_output ();
+
+  translate_range (&files[0], f0, l0, &tf0, &tl0);
+
+  if (deletes)
+    {
+      fprintf (outfile, "d");
+      /* For deletion, print just the starting line number from file 0
+	 and the number of lines deleted.  */
+      fprintf (outfile, "%d %d\n",
+	       tf0,
+	       (tl0 >= tf0 ? tl0 - tf0 + 1 : 1));	     
+    }
+
+  if (inserts)
+    {
+      fprintf (outfile, "a");
+
+      /* Take last-line-number from file 0 and # lines from file 1.  */
+      translate_range (&files[1], f1, l1, &tf1, &tl1);
+      fprintf (outfile, "%d %d\n",
+	       tl0,
+	       (tl1 >= tf1 ? tl1 - tf1 + 1 : 1));	     
+
+      /* Print the inserted lines.  */
+      for (i = f1; i <= l1; i++)
+	print_1_line ("", &files[1].linbuf[i]);
+    }
+}
diff --git a/gnu/usr.bin/diff/getopt.c b/gnu/usr.bin/diff/getopt.c
new file mode 100644
index 00000000000..21fa7fad286
--- /dev/null
+++ b/gnu/usr.bin/diff/getopt.c
@@ -0,0 +1,748 @@
+/* Getopt for GNU.
+   NOTE: getopt is now part of the C library, so if you don't know what
+   "Keep this file name-space clean" means, talk to roland@gnu.ai.mit.edu
+   before changing it!
+
+   Copyright (C) 1987, 88, 89, 90, 91, 92, 93, 94
+   	Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 2, or (at your option) any
+   later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* This tells Alpha OSF/1 not to define a getopt prototype in <stdio.h>.
+   Ditto for AIX 3.2 and <stdlib.h>.  */
+#ifndef _NO_PROTO
+#define _NO_PROTO
+#endif
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#ifndef __STDC__
+/* This is a separate conditional since some stdc systems
+   reject `defined (const)'.  */
+#ifndef const
+#define const
+#endif
+#endif
+
+#include <stdio.h>
+
+/* Comment out all this code if we are using the GNU C Library, and are not
+   actually compiling the library itself.  This code is part of the GNU C
+   Library, but also included in many other GNU distributions.  Compiling
+   and linking in this code is a waste when using the GNU C library
+   (especially if it is a shared library).  Rather than having every GNU
+   program understand `configure --with-gnu-libc' and omit the object files,
+   it is simpler to just do this in the source for each such file.  */
+
+#if defined (_LIBC) || !defined (__GNU_LIBRARY__)
+
+
+/* This needs to come after some library #include
+   to get __GNU_LIBRARY__ defined.  */
+#if defined(__GNU_LIBRARY__) || defined(__NetBSD__)
+/* Don't include stdlib.h for non-GNU C libraries because some of them
+   contain conflicting prototypes for getopt.  */
+#include <stdlib.h>
+#endif	/* GNU C library.  */
+
+/* This version of `getopt' appears to the caller like standard Unix `getopt'
+   but it behaves differently for the user, since it allows the user
+   to intersperse the options with the other arguments.
+
+   As `getopt' works, it permutes the elements of ARGV so that,
+   when it is done, all the options precede everything else.  Thus
+   all application programs are extended to handle flexible argument order.
+
+   Setting the environment variable POSIXLY_CORRECT disables permutation.
+   Then the behavior is completely standard.
+
+   GNU application programs can use a third alternative mode in which
+   they can distinguish the relative order of options and other arguments.  */
+
+#include "getopt.h"
+
+/* For communication from `getopt' to the caller.
+   When `getopt' finds an option that takes an argument,
+   the argument value is returned here.
+   Also, when `ordering' is RETURN_IN_ORDER,
+   each non-option ARGV-element is returned here.  */
+
+char *optarg = NULL;
+
+/* Index in ARGV of the next element to be scanned.
+   This is used for communication to and from the caller
+   and for communication between successive calls to `getopt'.
+
+   On entry to `getopt', zero means this is the first call; initialize.
+
+   When `getopt' returns EOF, this is the index of the first of the
+   non-option elements that the caller should itself scan.
+
+   Otherwise, `optind' communicates from one call to the next
+   how much of ARGV has been scanned so far.  */
+
+/* XXX 1003.2 says this must be 1 before any call.  */
+int optind = 0;
+
+/* The next char to be scanned in the option-element
+   in which the last option character we returned was found.
+   This allows us to pick up the scan where we left off.
+
+   If this is zero, or a null string, it means resume the scan
+   by advancing to the next ARGV-element.  */
+
+static char *nextchar;
+
+/* Callers store zero here to inhibit the error message
+   for unrecognized options.  */
+
+int opterr = 1;
+
+/* Set to an option character which was unrecognized.
+   This must be initialized on some systems to avoid linking in the
+   system's own getopt implementation.  */
+
+int optopt = '?';
+
+/* Describe how to deal with options that follow non-option ARGV-elements.
+
+   If the caller did not specify anything,
+   the default is REQUIRE_ORDER if the environment variable
+   POSIXLY_CORRECT is defined, PERMUTE otherwise.
+
+   REQUIRE_ORDER means don't recognize them as options;
+   stop option processing when the first non-option is seen.
+   This is what Unix does.
+   This mode of operation is selected by either setting the environment
+   variable POSIXLY_CORRECT, or using `+' as the first character
+   of the list of option characters.
+
+   PERMUTE is the default.  We permute the contents of ARGV as we scan,
+   so that eventually all the non-options are at the end.  This allows options
+   to be given in any order, even with programs that were not written to
+   expect this.
+
+   RETURN_IN_ORDER is an option available to programs that were written
+   to expect options and other ARGV-elements in any order and that care about
+   the ordering of the two.  We describe each non-option ARGV-element
+   as if it were the argument of an option with character code 1.
+   Using `-' as the first character of the list of option characters
+   selects this mode of operation.
+
+   The special argument `--' forces an end of option-scanning regardless
+   of the value of `ordering'.  In the case of RETURN_IN_ORDER, only
+   `--' can cause `getopt' to return EOF with `optind' != ARGC.  */
+
+static enum
+{
+  REQUIRE_ORDER, PERMUTE, RETURN_IN_ORDER
+} ordering;
+
+/* Value of POSIXLY_CORRECT environment variable.  */
+static char *posixly_correct;
+
+#if defined(__GNU_LIBRARY__) || defined(__NetBSD__)
+/* We want to avoid inclusion of string.h with non-GNU libraries
+   because there are many ways it can cause trouble.
+   On some systems, it contains special magic macros that don't work
+   in GCC.  */
+#include <string.h>
+#define	my_index	strchr
+#else
+
+/* Avoid depending on library functions or files
+   whose names are inconsistent.  */
+
+char *getenv ();
+
+static char *
+my_index (str, chr)
+     const char *str;
+     int chr;
+{
+  while (*str)
+    {
+      if (*str == chr)
+	return (char *) str;
+      str++;
+    }
+  return 0;
+}
+
+/* If using GCC, we can safely declare strlen this way.
+   If not using GCC, it is ok not to declare it.  */
+#ifdef __GNUC__
+/* Note that Motorola Delta 68k R3V7 comes with GCC but not stddef.h.
+   That was relevant to code that was here before.  */
+#ifndef __STDC__
+/* gcc with -traditional declares the built-in strlen to return int,
+   and has done so at least since version 2.4.5. -- rms.  */
+extern int strlen (const char *);
+#endif /* not __STDC__ */
+#endif /* __GNUC__ */
+
+#endif /* not __GNU_LIBRARY__ */
+
+/* Handle permutation of arguments.  */
+
+/* Describe the part of ARGV that contains non-options that have
+   been skipped.  `first_nonopt' is the index in ARGV of the first of them;
+   `last_nonopt' is the index after the last of them.  */
+
+static int first_nonopt;
+static int last_nonopt;
+
+/* Exchange two adjacent subsequences of ARGV.
+   One subsequence is elements [first_nonopt,last_nonopt)
+   which contains all the non-options that have been skipped so far.
+   The other is elements [last_nonopt,optind), which contains all
+   the options processed since those non-options were skipped.
+
+   `first_nonopt' and `last_nonopt' are relocated so that they describe
+   the new indices of the non-options in ARGV after they are moved.  */
+
+static void
+exchange (argv)
+     char **argv;
+{
+  int bottom = first_nonopt;
+  int middle = last_nonopt;
+  int top = optind;
+  char *tem;
+
+  /* Exchange the shorter segment with the far end of the longer segment.
+     That puts the shorter segment into the right place.
+     It leaves the longer segment in the right place overall,
+     but it consists of two parts that need to be swapped next.  */
+
+  while (top > middle && middle > bottom)
+    {
+      if (top - middle > middle - bottom)
+	{
+	  /* Bottom segment is the short one.  */
+	  int len = middle - bottom;
+	  register int i;
+
+	  /* Swap it with the top part of the top segment.  */
+	  for (i = 0; i < len; i++)
+	    {
+	      tem = argv[bottom + i];
+	      argv[bottom + i] = argv[top - (middle - bottom) + i];
+	      argv[top - (middle - bottom) + i] = tem;
+	    }
+	  /* Exclude the moved bottom segment from further swapping.  */
+	  top -= len;
+	}
+      else
+	{
+	  /* Top segment is the short one.  */
+	  int len = top - middle;
+	  register int i;
+
+	  /* Swap it with the bottom part of the bottom segment.  */
+	  for (i = 0; i < len; i++)
+	    {
+	      tem = argv[bottom + i];
+	      argv[bottom + i] = argv[middle + i];
+	      argv[middle + i] = tem;
+	    }
+	  /* Exclude the moved top segment from further swapping.  */
+	  bottom += len;
+	}
+    }
+
+  /* Update records for the slots the non-options now occupy.  */
+
+  first_nonopt += (optind - last_nonopt);
+  last_nonopt = optind;
+}
+
+/* Initialize the internal data when the first call is made.  */
+
+static const char *
+_getopt_initialize (optstring)
+     const char *optstring;
+{
+  /* Start processing options with ARGV-element 1 (since ARGV-element 0
+     is the program name); the sequence of previously skipped
+     non-option ARGV-elements is empty.  */
+
+  first_nonopt = last_nonopt = optind = 1;
+
+  nextchar = NULL;
+
+  posixly_correct = getenv ("POSIXLY_CORRECT");
+
+  /* Determine how to handle the ordering of options and nonoptions.  */
+
+  if (optstring[0] == '-')
+    {
+      ordering = RETURN_IN_ORDER;
+      ++optstring;
+    }
+  else if (optstring[0] == '+')
+    {
+      ordering = REQUIRE_ORDER;
+      ++optstring;
+    }
+  else if (posixly_correct != NULL)
+    ordering = REQUIRE_ORDER;
+  else
+    ordering = PERMUTE;
+
+  return optstring;
+}
+
+/* Scan elements of ARGV (whose length is ARGC) for option characters
+   given in OPTSTRING.
+
+   If an element of ARGV starts with '-', and is not exactly "-" or "--",
+   then it is an option element.  The characters of this element
+   (aside from the initial '-') are option characters.  If `getopt'
+   is called repeatedly, it returns successively each of the option characters
+   from each of the option elements.
+
+   If `getopt' finds another option character, it returns that character,
+   updating `optind' and `nextchar' so that the next call to `getopt' can
+   resume the scan with the following option character or ARGV-element.
+
+   If there are no more option characters, `getopt' returns `EOF'.
+   Then `optind' is the index in ARGV of the first ARGV-element
+   that is not an option.  (The ARGV-elements have been permuted
+   so that those that are not options now come last.)
+
+   OPTSTRING is a string containing the legitimate option characters.
+   If an option character is seen that is not listed in OPTSTRING,
+   return '?' after printing an error message.  If you set `opterr' to
+   zero, the error message is suppressed but we still return '?'.
+
+   If a char in OPTSTRING is followed by a colon, that means it wants an arg,
+   so the following text in the same ARGV-element, or the text of the following
+   ARGV-element, is returned in `optarg'.  Two colons mean an option that
+   wants an optional arg; if there is text in the current ARGV-element,
+   it is returned in `optarg', otherwise `optarg' is set to zero.
+
+   If OPTSTRING starts with `-' or `+', it requests different methods of
+   handling the non-option ARGV-elements.
+   See the comments about RETURN_IN_ORDER and REQUIRE_ORDER, above.
+
+   Long-named options begin with `--' instead of `-'.
+   Their names may be abbreviated as long as the abbreviation is unique
+   or is an exact match for some defined option.  If they have an
+   argument, it follows the option name in the same ARGV-element, separated
+   from the option name by a `=', or else the in next ARGV-element.
+   When `getopt' finds a long-named option, it returns 0 if that option's
+   `flag' field is nonzero, the value of the option's `val' field
+   if the `flag' field is zero.
+
+   The elements of ARGV aren't really const, because we permute them.
+   But we pretend they're const in the prototype to be compatible
+   with other systems.
+
+   LONGOPTS is a vector of `struct option' terminated by an
+   element containing a name which is zero.
+
+   LONGIND returns the index in LONGOPT of the long-named option found.
+   It is only valid when a long-named option has been found by the most
+   recent call.
+
+   If LONG_ONLY is nonzero, '-' as well as '--' can introduce
+   long-named options.  */
+
+int
+_getopt_internal (argc, argv, optstring, longopts, longind, long_only)
+     int argc;
+     char *const *argv;
+     const char *optstring;
+     const struct option *longopts;
+     int *longind;
+     int long_only;
+{
+  optarg = NULL;
+
+  if (optind == 0)
+    optstring = _getopt_initialize (optstring);
+
+  if (nextchar == NULL || *nextchar == '\0')
+    {
+      /* Advance to the next ARGV-element.  */
+
+      if (ordering == PERMUTE)
+	{
+	  /* If we have just processed some options following some non-options,
+	     exchange them so that the options come first.  */
+
+	  if (first_nonopt != last_nonopt && last_nonopt != optind)
+	    exchange ((char **) argv);
+	  else if (last_nonopt != optind)
+	    first_nonopt = optind;
+
+	  /* Skip any additional non-options
+	     and extend the range of non-options previously skipped.  */
+
+	  while (optind < argc
+		 && (argv[optind][0] != '-' || argv[optind][1] == '\0'))
+	    optind++;
+	  last_nonopt = optind;
+	}
+
+      /* The special ARGV-element `--' means premature end of options.
+	 Skip it like a null option,
+	 then exchange with previous non-options as if it were an option,
+	 then skip everything else like a non-option.  */
+
+      if (optind != argc && !strcmp (argv[optind], "--"))
+	{
+	  optind++;
+
+	  if (first_nonopt != last_nonopt && last_nonopt != optind)
+	    exchange ((char **) argv);
+	  else if (first_nonopt == last_nonopt)
+	    first_nonopt = optind;
+	  last_nonopt = argc;
+
+	  optind = argc;
+	}
+
+      /* If we have done all the ARGV-elements, stop the scan
+	 and back over any non-options that we skipped and permuted.  */
+
+      if (optind == argc)
+	{
+	  /* Set the next-arg-index to point at the non-options
+	     that we previously skipped, so the caller will digest them.  */
+	  if (first_nonopt != last_nonopt)
+	    optind = first_nonopt;
+	  return EOF;
+	}
+
+      /* If we have come to a non-option and did not permute it,
+	 either stop the scan or describe it to the caller and pass it by.  */
+
+      if ((argv[optind][0] != '-' || argv[optind][1] == '\0'))
+	{
+	  if (ordering == REQUIRE_ORDER)
+	    return EOF;
+	  optarg = argv[optind++];
+	  return 1;
+	}
+
+      /* We have found another option-ARGV-element.
+	 Skip the initial punctuation.  */
+
+      nextchar = (argv[optind] + 1
+		  + (longopts != NULL && argv[optind][1] == '-'));
+    }
+
+  /* Decode the current option-ARGV-element.  */
+
+  /* Check whether the ARGV-element is a long option.
+
+     If long_only and the ARGV-element has the form "-f", where f is
+     a valid short option, don't consider it an abbreviated form of
+     a long option that starts with f.  Otherwise there would be no
+     way to give the -f short option.
+
+     On the other hand, if there's a long option "fubar" and
+     the ARGV-element is "-fu", do consider that an abbreviation of
+     the long option, just like "--fu", and not "-f" with arg "u".
+
+     This distinction seems to be the most useful approach.  */
+
+  if (longopts != NULL
+      && (argv[optind][1] == '-'
+	  || (long_only && (argv[optind][2] || !my_index (optstring, argv[optind][1])))))
+    {
+      char *nameend;
+      const struct option *p;
+      const struct option *pfound = NULL;
+      int exact = 0;
+      int ambig = 0;
+      int indfound;
+      int option_index;
+
+      for (nameend = nextchar; *nameend && *nameend != '='; nameend++)
+	/* Do nothing.  */ ;
+
+      /* Test all long options for either exact match
+	 or abbreviated matches.  */
+      for (p = longopts, option_index = 0; p->name; p++, option_index++)
+	if (!strncmp (p->name, nextchar, nameend - nextchar))
+	  {
+	    if (nameend - nextchar == strlen (p->name))
+	      {
+		/* Exact match found.  */
+		pfound = p;
+		indfound = option_index;
+		exact = 1;
+		break;
+	      }
+	    else if (pfound == NULL)
+	      {
+		/* First nonexact match found.  */
+		pfound = p;
+		indfound = option_index;
+	      }
+	    else
+	      /* Second or later nonexact match found.  */
+	      ambig = 1;
+	  }
+
+      if (ambig && !exact)
+	{
+	  if (opterr)
+	    fprintf (stderr, "%s: option `%s' is ambiguous\n",
+		     argv[0], argv[optind]);
+	  nextchar += strlen (nextchar);
+	  optind++;
+	  return '?';
+	}
+
+      if (pfound != NULL)
+	{
+	  option_index = indfound;
+	  optind++;
+	  if (*nameend)
+	    {
+	      /* Don't test has_arg with >, because some C compilers don't
+		 allow it to be used on enums.  */
+	      if (pfound->has_arg)
+		optarg = nameend + 1;
+	      else
+		{
+		  if (opterr)
+		    {
+		      if (argv[optind - 1][1] == '-')
+			/* --option */
+			fprintf (stderr,
+				 "%s: option `--%s' doesn't allow an argument\n",
+				 argv[0], pfound->name);
+		      else
+			/* +option or -option */
+			fprintf (stderr,
+			     "%s: option `%c%s' doesn't allow an argument\n",
+			     argv[0], argv[optind - 1][0], pfound->name);
+		    }
+		  nextchar += strlen (nextchar);
+		  return '?';
+		}
+	    }
+	  else if (pfound->has_arg == 1)
+	    {
+	      if (optind < argc)
+		optarg = argv[optind++];
+	      else
+		{
+		  if (opterr)
+		    fprintf (stderr, "%s: option `%s' requires an argument\n",
+			     argv[0], argv[optind - 1]);
+		  nextchar += strlen (nextchar);
+		  return optstring[0] == ':' ? ':' : '?';
+		}
+	    }
+	  nextchar += strlen (nextchar);
+	  if (longind != NULL)
+	    *longind = option_index;
+	  if (pfound->flag)
+	    {
+	      *(pfound->flag) = pfound->val;
+	      return 0;
+	    }
+	  return pfound->val;
+	}
+
+      /* Can't find it as a long option.  If this is not getopt_long_only,
+	 or the option starts with '--' or is not a valid short
+	 option, then it's an error.
+	 Otherwise interpret it as a short option.  */
+      if (!long_only || argv[optind][1] == '-'
+	  || my_index (optstring, *nextchar) == NULL)
+	{
+	  if (opterr)
+	    {
+	      if (argv[optind][1] == '-')
+		/* --option */
+		fprintf (stderr, "%s: unrecognized option `--%s'\n",
+			 argv[0], nextchar);
+	      else
+		/* +option or -option */
+		fprintf (stderr, "%s: unrecognized option `%c%s'\n",
+			 argv[0], argv[optind][0], nextchar);
+	    }
+	  nextchar = (char *) "";
+	  optind++;
+	  return '?';
+	}
+    }
+
+  /* Look at and handle the next short option-character.  */
+
+  {
+    char c = *nextchar++;
+    char *temp = my_index (optstring, c);
+
+    /* Increment `optind' when we start to process its last character.  */
+    if (*nextchar == '\0')
+      ++optind;
+
+    if (temp == NULL || c == ':')
+      {
+	if (opterr)
+	  {
+	    if (posixly_correct)
+	      /* 1003.2 specifies the format of this message.  */
+	      fprintf (stderr, "%s: illegal option -- %c\n", argv[0], c);
+	    else
+	      fprintf (stderr, "%s: invalid option -- %c\n", argv[0], c);
+	  }
+	optopt = c;
+	return '?';
+      }
+    if (temp[1] == ':')
+      {
+	if (temp[2] == ':')
+	  {
+	    /* This is an option that accepts an argument optionally.  */
+	    if (*nextchar != '\0')
+	      {
+		optarg = nextchar;
+		optind++;
+	      }
+	    else
+	      optarg = NULL;
+	    nextchar = NULL;
+	  }
+	else
+	  {
+	    /* This is an option that requires an argument.  */
+	    if (*nextchar != '\0')
+	      {
+		optarg = nextchar;
+		/* If we end this ARGV-element by taking the rest as an arg,
+		   we must advance to the next element now.  */
+		optind++;
+	      }
+	    else if (optind == argc)
+	      {
+		if (opterr)
+		  {
+		    /* 1003.2 specifies the format of this message.  */
+		    fprintf (stderr, "%s: option requires an argument -- %c\n",
+			     argv[0], c);
+		  }
+		optopt = c;
+		if (optstring[0] == ':')
+		  c = ':';
+		else
+		  c = '?';
+	      }
+	    else
+	      /* We already incremented `optind' once;
+		 increment it again when taking next ARGV-elt as argument.  */
+	      optarg = argv[optind++];
+	    nextchar = NULL;
+	  }
+      }
+    return c;
+  }
+}
+
+int
+getopt (argc, argv, optstring)
+     int argc;
+     char *const *argv;
+     const char *optstring;
+{
+  return _getopt_internal (argc, argv, optstring,
+			   (const struct option *) 0,
+			   (int *) 0,
+			   0);
+}
+
+#endif	/* _LIBC or not __GNU_LIBRARY__.  */
+
+#ifdef TEST
+
+/* Compile with -DTEST to make an executable for use in testing
+   the above definition of `getopt'.  */
+
+int
+main (argc, argv)
+     int argc;
+     char **argv;
+{
+  int c;
+  int digit_optind = 0;
+
+  while (1)
+    {
+      int this_option_optind = optind ? optind : 1;
+
+      c = getopt (argc, argv, "abc:d:0123456789");
+      if (c == EOF)
+	break;
+
+      switch (c)
+	{
+	case '0':
+	case '1':
+	case '2':
+	case '3':
+	case '4':
+	case '5':
+	case '6':
+	case '7':
+	case '8':
+	case '9':
+	  if (digit_optind != 0 && digit_optind != this_option_optind)
+	    printf ("digits occur in two different argv-elements.\n");
+	  digit_optind = this_option_optind;
+	  printf ("option %c\n", c);
+	  break;
+
+	case 'a':
+	  printf ("option a\n");
+	  break;
+
+	case 'b':
+	  printf ("option b\n");
+	  break;
+
+	case 'c':
+	  printf ("option c with value `%s'\n", optarg);
+	  break;
+
+	case '?':
+	  break;
+
+	default:
+	  printf ("?? getopt returned character code 0%o ??\n", c);
+	}
+    }
+
+  if (optind < argc)
+    {
+      printf ("non-option ARGV-elements: ");
+      while (optind < argc)
+	printf ("%s ", argv[optind++]);
+      printf ("\n");
+    }
+
+  exit (0);
+}
+
+#endif /* TEST */
diff --git a/gnu/usr.bin/diff/getopt.h b/gnu/usr.bin/diff/getopt.h
new file mode 100644
index 00000000000..45541f5ac0f
--- /dev/null
+++ b/gnu/usr.bin/diff/getopt.h
@@ -0,0 +1,129 @@
+/* Declarations for getopt.
+   Copyright (C) 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 2, or (at your option) any
+   later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#ifndef _GETOPT_H
+#define _GETOPT_H 1
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+/* For communication from `getopt' to the caller.
+   When `getopt' finds an option that takes an argument,
+   the argument value is returned here.
+   Also, when `ordering' is RETURN_IN_ORDER,
+   each non-option ARGV-element is returned here.  */
+
+extern char *optarg;
+
+/* Index in ARGV of the next element to be scanned.
+   This is used for communication to and from the caller
+   and for communication between successive calls to `getopt'.
+
+   On entry to `getopt', zero means this is the first call; initialize.
+
+   When `getopt' returns EOF, this is the index of the first of the
+   non-option elements that the caller should itself scan.
+
+   Otherwise, `optind' communicates from one call to the next
+   how much of ARGV has been scanned so far.  */
+
+extern int optind;
+
+/* Callers store zero here to inhibit the error message `getopt' prints
+   for unrecognized options.  */
+
+extern int opterr;
+
+/* Set to an option character which was unrecognized.  */
+
+extern int optopt;
+
+/* Describe the long-named options requested by the application.
+   The LONG_OPTIONS argument to getopt_long or getopt_long_only is a vector
+   of `struct option' terminated by an element containing a name which is
+   zero.
+
+   The field `has_arg' is:
+   no_argument		(or 0) if the option does not take an argument,
+   required_argument	(or 1) if the option requires an argument,
+   optional_argument 	(or 2) if the option takes an optional argument.
+
+   If the field `flag' is not NULL, it points to a variable that is set
+   to the value given in the field `val' when the option is found, but
+   left unchanged if the option is not found.
+
+   To have a long-named option do something other than set an `int' to
+   a compiled-in constant, such as set a value from `optarg', set the
+   option's `flag' field to zero and its `val' field to a nonzero
+   value (the equivalent single-letter option character, if there is
+   one).  For long options that have a zero `flag' field, `getopt'
+   returns the contents of the `val' field.  */
+
+struct option
+{
+#if	__STDC__
+  const char *name;
+#else
+  char *name;
+#endif
+  /* has_arg can't be an enum because some compilers complain about
+     type mismatches in all the code that assumes it is an int.  */
+  int has_arg;
+  int *flag;
+  int val;
+};
+
+/* Names for the values of the `has_arg' field of `struct option'.  */
+
+#define	no_argument		0
+#define required_argument	1
+#define optional_argument	2
+
+#if __STDC__
+#if defined(__GNU_LIBRARY__)
+/* Many other libraries have conflicting prototypes for getopt, with
+   differences in the consts, in stdlib.h.  To avoid compilation
+   errors, only prototype getopt for the GNU C library.  */
+extern int getopt (int argc, char *const *argv, const char *shortopts);
+#else /* not __GNU_LIBRARY__ */
+extern int getopt ();
+#endif /* not __GNU_LIBRARY__ */
+extern int getopt_long (int argc, char *const *argv, const char *shortopts,
+		        const struct option *longopts, int *longind);
+extern int getopt_long_only (int argc, char *const *argv,
+			     const char *shortopts,
+		             const struct option *longopts, int *longind);
+
+/* Internal only.  Users should not call this directly.  */
+extern int _getopt_internal (int argc, char *const *argv,
+			     const char *shortopts,
+		             const struct option *longopts, int *longind,
+			     int long_only);
+#else /* not __STDC__ */
+extern int getopt ();
+extern int getopt_long ();
+extern int getopt_long_only ();
+
+extern int _getopt_internal ();
+#endif /* not __STDC__ */
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif /* _GETOPT_H */
diff --git a/gnu/usr.bin/diff/getopt1.c b/gnu/usr.bin/diff/getopt1.c
new file mode 100644
index 00000000000..725c653bbcc
--- /dev/null
+++ b/gnu/usr.bin/diff/getopt1.c
@@ -0,0 +1,180 @@
+/* getopt_long and getopt_long_only entry points for GNU getopt.
+   Copyright (C) 1987, 88, 89, 90, 91, 92, 1993
+	Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 2, or (at your option) any
+   later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include "getopt.h"
+
+#ifndef __STDC__
+/* This is a separate conditional since some stdc systems
+   reject `defined (const)'.  */
+#ifndef const
+#define const
+#endif
+#endif
+
+#include <stdio.h>
+
+/* Comment out all this code if we are using the GNU C Library, and are not
+   actually compiling the library itself.  This code is part of the GNU C
+   Library, but also included in many other GNU distributions.  Compiling
+   and linking in this code is a waste when using the GNU C library
+   (especially if it is a shared library).  Rather than having every GNU
+   program understand `configure --with-gnu-libc' and omit the object files,
+   it is simpler to just do this in the source for each such file.  */
+
+#if defined (_LIBC) || !defined (__GNU_LIBRARY__)
+
+
+/* This needs to come after some library #include
+   to get __GNU_LIBRARY__ defined.  */
+#ifdef __GNU_LIBRARY__
+#include <stdlib.h>
+#else
+char *getenv ();
+#endif
+
+#ifndef	NULL
+#define NULL 0
+#endif
+
+int
+getopt_long (argc, argv, options, long_options, opt_index)
+     int argc;
+     char *const *argv;
+     const char *options;
+     const struct option *long_options;
+     int *opt_index;
+{
+  return _getopt_internal (argc, argv, options, long_options, opt_index, 0);
+}
+
+/* Like getopt_long, but '-' as well as '--' can indicate a long option.
+   If an option that starts with '-' (not '--') doesn't match a long option,
+   but does match a short option, it is parsed as a short option
+   instead.  */
+
+int
+getopt_long_only (argc, argv, options, long_options, opt_index)
+     int argc;
+     char *const *argv;
+     const char *options;
+     const struct option *long_options;
+     int *opt_index;
+{
+  return _getopt_internal (argc, argv, options, long_options, opt_index, 1);
+}
+
+
+#endif	/* _LIBC or not __GNU_LIBRARY__.  */
+
+#ifdef TEST
+
+#include <stdio.h>
+
+int
+main (argc, argv)
+     int argc;
+     char **argv;
+{
+  int c;
+  int digit_optind = 0;
+
+  while (1)
+    {
+      int this_option_optind = optind ? optind : 1;
+      int option_index = 0;
+      static struct option long_options[] =
+      {
+	{"add", 1, 0, 0},
+	{"append", 0, 0, 0},
+	{"delete", 1, 0, 0},
+	{"verbose", 0, 0, 0},
+	{"create", 0, 0, 0},
+	{"file", 1, 0, 0},
+	{0, 0, 0, 0}
+      };
+
+      c = getopt_long (argc, argv, "abc:d:0123456789",
+		       long_options, &option_index);
+      if (c == EOF)
+	break;
+
+      switch (c)
+	{
+	case 0:
+	  printf ("option %s", long_options[option_index].name);
+	  if (optarg)
+	    printf (" with arg %s", optarg);
+	  printf ("\n");
+	  break;
+
+	case '0':
+	case '1':
+	case '2':
+	case '3':
+	case '4':
+	case '5':
+	case '6':
+	case '7':
+	case '8':
+	case '9':
+	  if (digit_optind != 0 && digit_optind != this_option_optind)
+	    printf ("digits occur in two different argv-elements.\n");
+	  digit_optind = this_option_optind;
+	  printf ("option %c\n", c);
+	  break;
+
+	case 'a':
+	  printf ("option a\n");
+	  break;
+
+	case 'b':
+	  printf ("option b\n");
+	  break;
+
+	case 'c':
+	  printf ("option c with value `%s'\n", optarg);
+	  break;
+
+	case 'd':
+	  printf ("option d with value `%s'\n", optarg);
+	  break;
+
+	case '?':
+	  break;
+
+	default:
+	  printf ("?? getopt returned character code 0%o ??\n", c);
+	}
+    }
+
+  if (optind < argc)
+    {
+      printf ("non-option ARGV-elements: ");
+      while (optind < argc)
+	printf ("%s ", argv[optind++]);
+      printf ("\n");
+    }
+
+  exit (0);
+}
+
+#endif /* TEST */
diff --git a/gnu/usr.bin/diff/ifdef.c b/gnu/usr.bin/diff/ifdef.c
new file mode 100644
index 00000000000..2834cbdfa23
--- /dev/null
+++ b/gnu/usr.bin/diff/ifdef.c
@@ -0,0 +1,428 @@
+/* #ifdef-format output routines for GNU DIFF.
+   Copyright (C) 1989, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY.  No author or distributor
+accepts responsibility to anyone for the consequences of using it
+or for whether it serves any particular purpose or works at all,
+unless he says so in writing.  Refer to the GNU DIFF General Public
+License for full details.
+
+Everyone is granted permission to copy, modify and redistribute
+GNU DIFF, but only under the conditions described in the
+GNU DIFF General Public License.   A copy of this license is
+supposed to have been given to you along with GNU DIFF so you
+can know your rights and responsibilities.  It should be in a
+file named COPYING.  Among other things, the copyright notice
+and this notice must be preserved on all copies.  */
+
+
+#include "diff.h"
+
+struct group
+{
+  struct file_data const *file;
+  int from, upto; /* start and limit lines for this group of lines */
+};
+
+static char *format_group PARAMS((FILE *, char *, int, struct group const *));
+static char *scan_char_literal PARAMS((char *, int *));
+static char *scan_printf_spec PARAMS((char *));
+static int groups_letter_value PARAMS((struct group const *, int));
+static void format_ifdef PARAMS((char *, int, int, int, int));
+static void print_ifdef_hunk PARAMS((struct change *));
+static void print_ifdef_lines PARAMS((FILE *, char *, struct group const *));
+
+static int next_line;
+
+/* Print the edit-script SCRIPT as a merged #ifdef file.  */
+
+void
+print_ifdef_script (script)
+     struct change *script;
+{
+  next_line = - files[0].prefix_lines;
+  print_script (script, find_change, print_ifdef_hunk);
+  if (next_line < files[0].valid_lines)
+    {
+      begin_output ();
+      format_ifdef (group_format[UNCHANGED], next_line, files[0].valid_lines,
+		    next_line - files[0].valid_lines + files[1].valid_lines,
+		    files[1].valid_lines);
+    }
+}
+
+/* Print a hunk of an ifdef diff.
+   This is a contiguous portion of a complete edit script,
+   describing changes in consecutive lines.  */
+
+static void
+print_ifdef_hunk (hunk)
+     struct change *hunk;
+{
+  int first0, last0, first1, last1, deletes, inserts;
+  char *format;
+
+  /* Determine range of line numbers involved in each file.  */
+  analyze_hunk (hunk, &first0, &last0, &first1, &last1, &deletes, &inserts);
+  if (inserts)
+    format = deletes ? group_format[CHANGED] : group_format[NEW];
+  else if (deletes)
+    format = group_format[OLD];
+  else
+    return;
+
+  begin_output ();
+
+  /* Print lines up to this change.  */
+  if (next_line < first0)
+    format_ifdef (group_format[UNCHANGED], next_line, first0,
+		  next_line - first0 + first1, first1);
+
+  /* Print this change.  */
+  next_line = last0 + 1;
+  format_ifdef (format, first0, next_line, first1, last1 + 1);
+}
+
+/* Print a set of lines according to FORMAT.
+   Lines BEG0 up to END0 are from the first file;
+   lines BEG1 up to END1 are from the second file.  */
+
+static void
+format_ifdef (format, beg0, end0, beg1, end1)
+     char *format;
+     int beg0, end0, beg1, end1;
+{
+  struct group groups[2];
+
+  groups[0].file = &files[0];
+  groups[0].from = beg0;
+  groups[0].upto = end0;
+  groups[1].file = &files[1];
+  groups[1].from = beg1;
+  groups[1].upto = end1;
+  format_group (outfile, format, '\0', groups);
+}
+
+/* Print to file OUT a set of lines according to FORMAT.
+   The format ends at the first free instance of ENDCHAR.
+   Yield the address of the terminating character.
+   GROUPS specifies which lines to print.
+   If OUT is zero, do not actually print anything; just scan the format.  */
+
+static char *
+format_group (out, format, endchar, groups)
+     register FILE *out;
+     char *format;
+     int endchar;
+     struct group const *groups;
+{
+  register char c;
+  register char *f = format;
+
+  while ((c = *f) != endchar && c != 0)
+    {
+      f++;
+      if (c == '%')
+	{
+	  char *spec = f;
+	  switch ((c = *f++))
+	    {
+	    case '%':
+	      break;
+
+	    case '(':
+	      /* Print if-then-else format e.g. `%(n=1?thenpart:elsepart)'.  */
+	      {
+		int i, value[2];
+		FILE *thenout, *elseout;
+
+		for (i = 0; i < 2; i++)
+		  {
+		    unsigned char f0 = f[0];
+		    if (ISDIGIT (f0))
+		      {
+			value[i] = atoi (f);
+			while (ISDIGIT ((unsigned char) *++f))
+			  continue;
+		      }
+		    else
+		      {
+			value[i] = groups_letter_value (groups, f0);
+			if (value[i] < 0)
+			  goto bad_format;
+			f++;
+		      }
+		    if (*f++ != "=?"[i])
+		      goto bad_format;
+		  }
+		if (value[0] == value[1])
+		  thenout = out, elseout = 0;
+		else
+		  thenout = 0, elseout = out;
+		f = format_group (thenout, f, ':', groups);
+		if (*f)
+		  {
+		    f = format_group (elseout, f + 1, ')', groups);
+		    if (*f)
+		      f++;
+		  }
+	      }
+	      continue;
+
+	    case '<':
+	      /* Print lines deleted from first file.  */
+	      print_ifdef_lines (out, line_format[OLD], &groups[0]);
+	      continue;
+
+	    case '=':
+	      /* Print common lines.  */
+	      print_ifdef_lines (out, line_format[UNCHANGED], &groups[0]);
+	      continue;
+
+	    case '>':
+	      /* Print lines inserted from second file.  */
+	      print_ifdef_lines (out, line_format[NEW], &groups[1]);
+	      continue;
+
+	    default:
+	      {
+		int value;
+		char *speclim;
+
+		f = scan_printf_spec (spec);
+		if (!f)
+		  goto bad_format;
+		speclim = f;
+		c = *f++;
+		switch (c)
+		  {
+		    case '\'':
+		      f = scan_char_literal (f, &value);
+		      if (!f)
+			goto bad_format;
+		      break;
+
+		    default:
+		      value = groups_letter_value (groups, c);
+		      if (value < 0)
+			goto bad_format;
+		      break;
+		  }
+		if (out)
+		  {
+		    /* Temporarily replace e.g. "%3dnx" with "%3d\0x".  */
+		    *speclim = 0;
+		    fprintf (out, spec - 1, value);
+		    /* Undo the temporary replacement.  */
+		    *speclim = c;
+		  }
+	      }
+	      continue;
+
+	    bad_format:
+	      c = '%';
+	      f = spec;
+	      break;
+	    }
+	}
+      if (out)
+	putc (c, out);
+    }
+  return f;
+}
+
+/* For the line group pair G, return the number corresponding to LETTER.
+   Return -1 if LETTER is not a group format letter.  */
+static int
+groups_letter_value (g, letter)
+     struct group const *g;
+     int letter;
+{
+  if (ISUPPER (letter))
+    {
+      g++;
+      letter = tolower (letter);
+    }
+  switch (letter)
+    {
+      case 'e': return translate_line_number (g->file, g->from) - 1;
+      case 'f': return translate_line_number (g->file, g->from);
+      case 'l': return translate_line_number (g->file, g->upto) - 1;
+      case 'm': return translate_line_number (g->file, g->upto);
+      case 'n': return g->upto - g->from;
+      default: return -1;
+    }
+}
+
+/* Print to file OUT, using FORMAT to print the line group GROUP.
+   But do nothing if OUT is zero.  */
+static void
+print_ifdef_lines (out, format, group)
+     register FILE *out;
+     char *format;
+     struct group const *group;
+{
+  struct file_data const *file = group->file;
+  char const * const *linbuf = file->linbuf;
+  int from = group->from, upto = group->upto;
+
+  if (!out)
+    return;
+
+  /* If possible, use a single fwrite; it's faster.  */
+  if (!tab_expand_flag && format[0] == '%')
+    {
+      if (format[1] == 'l' && format[2] == '\n' && !format[3])
+	{
+	  fwrite (linbuf[from], sizeof (char),
+		  linbuf[upto] + (linbuf[upto][-1] != '\n') -  linbuf[from],
+		  out);
+	  return;
+	}
+      if (format[1] == 'L' && !format[2])
+	{
+	  fwrite (linbuf[from], sizeof (char),
+		  linbuf[upto] -  linbuf[from], out);
+	  return;
+	}
+    }
+
+  for (;  from < upto;  from++)
+    {
+      register char c;
+      register char *f = format;
+
+      while ((c = *f++) != 0)
+	{
+	  if (c == '%')
+	    {
+	      char *spec = f;
+	      switch ((c = *f++))
+		{
+		case '%':
+		  break;
+
+		case 'l':
+		  output_1_line (linbuf[from],
+				 linbuf[from + 1]
+				   - (linbuf[from + 1][-1] == '\n'), 0, 0);
+		  continue;
+
+		case 'L':
+		  output_1_line (linbuf[from], linbuf[from + 1], 0, 0);
+		  continue;
+
+		default:
+		  {
+		    int value;
+		    char *speclim;
+
+		    f = scan_printf_spec (spec);
+		    if (!f)
+		      goto bad_format;
+		    speclim = f;
+		    c = *f++;
+		    switch (c)
+		      {
+			case '\'':
+			  f = scan_char_literal (f, &value);
+			  if (!f)
+			    goto bad_format;
+			  break;
+
+			case 'n':
+			  value = translate_line_number (file, from);
+			  break;
+
+			default:
+			  goto bad_format;
+		      }
+		    /* Temporarily replace e.g. "%3dnx" with "%3d\0x".  */
+		    *speclim = 0;
+		    fprintf (out, spec - 1, value);
+		    /* Undo the temporary replacement.  */
+		    *speclim = c;
+		  }
+		  continue;
+
+		bad_format:
+		  c = '%';
+		  f = spec;
+		  break;
+		}
+	    }
+	  putc (c, out);
+	}
+    }
+}
+
+/* Scan the character literal represented in the string LIT; LIT points just
+   after the initial apostrophe.  Put the literal's value into *INTPTR.
+   Yield the address of the first character after the closing apostrophe,
+   or zero if the literal is ill-formed.  */
+static char *
+scan_char_literal (lit, intptr)
+     char *lit;
+     int *intptr;
+{
+  register char *p = lit;
+  int value, digits;
+  char c = *p++;
+
+  switch (c)
+    {
+      case 0:
+      case '\'':
+	return 0;
+
+      case '\\':
+	value = 0;
+	while ((c = *p++) != '\'')
+	  {
+	    unsigned digit = c - '0';
+	    if (8 <= digit)
+	      return 0;
+	    value = 8 * value + digit;
+	  }
+	digits = p - lit - 2;
+	if (! (1 <= digits && digits <= 3))
+	  return 0;
+	break;
+
+      default:
+	value = c;
+	if (*p++ != '\'')
+	  return 0;
+	break;
+    }
+  *intptr = value;
+  return p;
+}
+
+/* Scan optional printf-style SPEC of the form `-*[0-9]*(.[0-9]*)?[cdoxX]'.
+   Return the address of the character following SPEC, or zero if failure.  */
+static char *
+scan_printf_spec (spec)
+     register char *spec;
+{
+  register unsigned char c;
+
+  while ((c = *spec++) == '-')
+    continue;
+  while (ISDIGIT (c))
+    c = *spec++;
+  if (c == '.')
+    while (ISDIGIT (c = *spec++))
+      continue;
+  switch (c)
+    {
+      case 'c': case 'd': case 'o': case 'x': case 'X':
+	return spec;
+
+      default:
+	return 0;
+    }
+}
diff --git a/gnu/usr.bin/diff/io.c b/gnu/usr.bin/diff/io.c
new file mode 100644
index 00000000000..66059155109
--- /dev/null
+++ b/gnu/usr.bin/diff/io.c
@@ -0,0 +1,714 @@
+/* File I/O for GNU DIFF.
+   Copyright (C) 1988, 1989, 1992, 1993, 1994 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "diff.h"
+
+/* Rotate a value n bits to the left. */
+#define UINT_BIT (sizeof (unsigned) * CHAR_BIT)
+#define ROL(v, n) ((v) << (n) | (v) >> (UINT_BIT - (n)))
+
+/* Given a hash value and a new character, return a new hash value. */
+#define HASH(h, c) ((c) + ROL (h, 7))
+
+/* Guess remaining number of lines from number N of lines so far,
+   size S so far, and total size T.  */
+#define GUESS_LINES(n,s,t) (((t) - (s)) / ((n) < 10 ? 32 : (s) / ((n)-1)) + 5)
+
+/* Type used for fast prefix comparison in find_identical_ends.  */
+#ifndef word
+#define word int
+#endif
+
+/* Lines are put into equivalence classes (of lines that match in line_cmp).
+   Each equivalence class is represented by one of these structures,
+   but only while the classes are being computed.
+   Afterward, each class is represented by a number.  */
+struct equivclass
+{
+  int next;	/* Next item in this bucket. */
+  unsigned hash;	/* Hash of lines in this class.  */
+  char const *line;	/* A line that fits this class. */
+  size_t length;	/* That line's length, not counting its newline.  */
+};
+
+/* Hash-table: array of buckets, each being a chain of equivalence classes.
+   buckets[-1] is reserved for incomplete lines.  */
+static int *buckets;
+
+/* Number of buckets in the hash table array, not counting buckets[-1]. */
+static int nbuckets;
+
+/* Array in which the equivalence classes are allocated.
+   The bucket-chains go through the elements in this array.
+   The number of an equivalence class is its index in this array.  */
+static struct equivclass *equivs;
+
+/* Index of first free element in the array `equivs'.  */
+static int equivs_index;
+
+/* Number of elements allocated in the array `equivs'.  */
+static int equivs_alloc;
+
+static void find_and_hash_each_line PARAMS((struct file_data *));
+static void find_identical_ends PARAMS((struct file_data[]));
+static void prepare_text_end PARAMS((struct file_data *));
+
+/* Check for binary files and compare them for exact identity.  */
+
+/* Return 1 if BUF contains a non text character.
+   SIZE is the number of characters in BUF.  */
+
+#define binary_file_p(buf, size) (memchr (buf, '\0', size) != 0)
+
+/* Get ready to read the current file.
+   Return nonzero if SKIP_TEST is zero,
+   and if it appears to be a binary file.  */
+
+int
+sip (current, skip_test)
+     struct file_data *current;
+     int skip_test;
+{
+  /* If we have a nonexistent file at this stage, treat it as empty.  */
+  if (current->desc < 0)
+    {
+      /* Leave room for a sentinel.  */
+      current->bufsize = sizeof (word);
+      current->buffer = xmalloc (current->bufsize);
+    }
+  else
+    {
+      current->bufsize = STAT_BLOCKSIZE (current->stat);
+      current->buffer = xmalloc (current->bufsize);
+
+      if (! skip_test)
+	{
+	  /* Check first part of file to see if it's a binary file.  */
+#if HAVE_SETMODE
+	  int oldmode = setmode (current->desc, O_BINARY);
+#endif
+	  size_t n = read (current->desc, current->buffer, current->bufsize);
+	  if (n == -1)
+	    pfatal_with_name (current->name);
+	  current->buffered_chars = n;
+#if HAVE_SETMODE
+	  if (oldmode != O_BINARY)
+	    {
+	      if (lseek (current->desc, - (off_t) n, SEEK_CUR) == -1)
+		pfatal_with_name (current->name);
+	      setmode (current->desc, oldmode);
+	      current->buffered_chars = 0;
+	    }
+#endif
+	  return binary_file_p (current->buffer, n);
+	}
+    }
+
+  current->buffered_chars = 0;
+  return 0;
+}
+
+/* Slurp the rest of the current file completely into memory.  */
+
+void
+slurp (current)
+     struct file_data *current;
+{
+  size_t cc;
+
+  if (current->desc < 0)
+    /* The file is nonexistent.  */
+    ;
+  else if (S_ISREG (current->stat.st_mode))
+    {
+      /* It's a regular file; slurp in the rest all at once.  */
+
+      /* Get the size out of the stat block.
+	 Allocate enough room for appended newline and sentinel.  */
+      cc = current->stat.st_size + 1 + sizeof (word);
+      if (current->bufsize < cc)
+	{
+	  current->bufsize = cc;
+	  current->buffer = xrealloc (current->buffer, cc);
+	}
+
+      if (current->buffered_chars < current->stat.st_size)
+	{
+	  cc = read (current->desc,
+		     current->buffer + current->buffered_chars,
+		     current->stat.st_size - current->buffered_chars);
+	  if (cc == -1)
+	    pfatal_with_name (current->name);
+	  current->buffered_chars += cc;
+	}
+    }
+  /* It's not a regular file; read it, growing the buffer as needed.  */
+  else if (always_text_flag || current->buffered_chars != 0)
+    {
+      for (;;)
+	{
+	  if (current->buffered_chars == current->bufsize)
+	    {
+	      current->bufsize = current->bufsize * 2;
+	      current->buffer = xrealloc (current->buffer, current->bufsize);
+	    }
+	  cc = read (current->desc,
+		     current->buffer + current->buffered_chars,
+		     current->bufsize - current->buffered_chars);
+	  if (cc == 0)
+	    break;
+	  if (cc == -1)
+	    pfatal_with_name (current->name);
+	  current->buffered_chars += cc;
+	}
+      /* Allocate just enough room for appended newline and sentinel.  */
+      current->bufsize = current->buffered_chars + 1 + sizeof (word);
+      current->buffer = xrealloc (current->buffer, current->bufsize);
+    }
+}
+
+/* Split the file into lines, simultaneously computing the equivalence class for
+   each line. */
+
+static void
+find_and_hash_each_line (current)
+     struct file_data *current;
+{
+  unsigned h;
+  unsigned char const *p = (unsigned char const *) current->prefix_end;
+  unsigned char c;
+  int i, *bucket;
+  size_t length;
+
+  /* Cache often-used quantities in local variables to help the compiler.  */
+  char const **linbuf = current->linbuf;
+  int alloc_lines = current->alloc_lines;
+  int line = 0;
+  int linbuf_base = current->linbuf_base;
+  int *cureqs = (int *) xmalloc (alloc_lines * sizeof (int));
+  struct equivclass *eqs = equivs;
+  int eqs_index = equivs_index;
+  int eqs_alloc = equivs_alloc;
+  char const *suffix_begin = current->suffix_begin;
+  char const *bufend = current->buffer + current->buffered_chars;
+  int use_line_cmp = ignore_some_line_changes;
+
+  while ((char const *) p < suffix_begin)
+    {
+      char const *ip = (char const *) p;
+
+      /* Compute the equivalence class for this line.  */
+
+      h = 0;
+
+      /* Hash this line until we find a newline. */
+      if (ignore_case_flag)
+	{
+	  if (ignore_all_space_flag)
+	    while ((c = *p++) != '\n')
+	      {
+		if (! ISSPACE (c))
+		  h = HASH (h, ISUPPER (c) ? tolower (c) : c);
+	      }
+	  else if (ignore_space_change_flag)
+	    while ((c = *p++) != '\n')
+	      {
+		if (ISSPACE (c))
+		  {
+		    for (;;)
+		      {
+			c = *p++;
+			if (!ISSPACE (c))
+			  break;
+			if (c == '\n')
+			  goto hashing_done;
+		      }
+		    h = HASH (h, ' ');
+		  }
+		/* C is now the first non-space.  */
+		h = HASH (h, ISUPPER (c) ? tolower (c) : c);
+	      }
+	  else
+	    while ((c = *p++) != '\n')
+	      h = HASH (h, ISUPPER (c) ? tolower (c) : c);
+	}
+      else
+	{
+	  if (ignore_all_space_flag)
+	    while ((c = *p++) != '\n')
+	      {
+		if (! ISSPACE (c))
+		  h = HASH (h, c);
+	      }
+	  else if (ignore_space_change_flag)
+	    while ((c = *p++) != '\n')
+	      {
+		if (ISSPACE (c))
+		  {
+		    for (;;)
+		      {
+			c = *p++;
+			if (!ISSPACE (c))
+			  break;
+			if (c == '\n')
+			  goto hashing_done;
+		      }
+		    h = HASH (h, ' ');
+		  }
+		/* C is now the first non-space.  */
+		h = HASH (h, c);
+	      }
+	  else
+	    while ((c = *p++) != '\n')
+	      h = HASH (h, c);
+	}
+   hashing_done:;
+
+      bucket = &buckets[h % nbuckets];
+      length = (char const *) p - ip - 1;
+
+      if ((char const *) p == bufend
+	  && current->missing_newline
+	  && ROBUST_OUTPUT_STYLE (output_style))
+	{
+	  /* This line is incomplete.  If this is significant,
+	     put the line into bucket[-1].  */
+	  if (! (ignore_space_change_flag | ignore_all_space_flag))
+	    bucket = &buckets[-1];
+
+	  /* Omit the inserted newline when computing linbuf later.  */
+	  p--;
+	  bufend = suffix_begin = (char const *) p;
+	}
+
+      for (i = *bucket;  ;  i = eqs[i].next)
+	if (!i)
+	  {
+	    /* Create a new equivalence class in this bucket. */
+	    i = eqs_index++;
+	    if (i == eqs_alloc)
+	      eqs = (struct equivclass *)
+		      xrealloc (eqs, (eqs_alloc*=2) * sizeof(*eqs));
+	    eqs[i].next = *bucket;
+	    eqs[i].hash = h;
+	    eqs[i].line = ip;
+	    eqs[i].length = length;
+	    *bucket = i;
+	    break;
+	  }
+	else if (eqs[i].hash == h)
+	  {
+	    char const *eqline = eqs[i].line;
+
+	    /* Reuse existing equivalence class if the lines are identical.
+	       This detects the common case of exact identity
+	       faster than complete comparison would.  */
+	    if (eqs[i].length == length && memcmp (eqline, ip, length) == 0)
+	      break;
+
+	    /* Reuse existing class if line_cmp reports the lines equal.  */
+	    if (use_line_cmp && line_cmp (eqline, ip) == 0)
+	      break;
+	  }
+
+      /* Maybe increase the size of the line table. */
+      if (line == alloc_lines)
+	{
+	  /* Double (alloc_lines - linbuf_base) by adding to alloc_lines.  */
+	  alloc_lines = 2 * alloc_lines - linbuf_base;
+	  cureqs = (int *) xrealloc (cureqs, alloc_lines * sizeof (*cureqs));
+	  linbuf = (char const **) xrealloc (linbuf + linbuf_base,
+					     (alloc_lines - linbuf_base)
+					     * sizeof (*linbuf))
+		   - linbuf_base;
+	}
+      linbuf[line] = ip;
+      cureqs[line] = i;
+      ++line;
+    }
+
+  current->buffered_lines = line;
+
+  for (i = 0;  ;  i++)
+    {
+      /* Record the line start for lines in the suffix that we care about.
+	 Record one more line start than lines,
+	 so that we can compute the length of any buffered line.  */
+      if (line == alloc_lines)
+	{
+	  /* Double (alloc_lines - linbuf_base) by adding to alloc_lines.  */
+	  alloc_lines = 2 * alloc_lines - linbuf_base;
+	  linbuf = (char const **) xrealloc (linbuf + linbuf_base,
+					     (alloc_lines - linbuf_base)
+					     * sizeof (*linbuf))
+		   - linbuf_base;
+	}
+      linbuf[line] = (char const *) p;
+
+      if ((char const *) p == bufend)
+	break;
+
+      if (context <= i && no_diff_means_no_output)
+	break;
+
+      line++;
+
+      while (*p++ != '\n')
+	;
+    }
+
+  /* Done with cache in local variables.  */
+  current->linbuf = linbuf;
+  current->valid_lines = line;
+  current->alloc_lines = alloc_lines;
+  current->equivs = cureqs;
+  equivs = eqs;
+  equivs_alloc = eqs_alloc;
+  equivs_index = eqs_index;
+}
+
+/* Prepare the end of the text.  Make sure it's initialized.
+   Make sure text ends in a newline,
+   but remember that we had to add one.  */
+
+static void
+prepare_text_end (current)
+     struct file_data *current;
+{
+  size_t buffered_chars = current->buffered_chars;
+  char *p = current->buffer;
+
+  if (buffered_chars == 0 || p[buffered_chars - 1] == '\n')
+    current->missing_newline = 0;
+  else
+    {
+      p[buffered_chars++] = '\n';
+      current->buffered_chars = buffered_chars;
+      current->missing_newline = 1;
+    }
+
+  /* Don't use uninitialized storage when planting or using sentinels.  */
+  if (p)
+    bzero (p + buffered_chars, sizeof (word));
+}
+
+/* Given a vector of two file_data objects, find the identical
+   prefixes and suffixes of each object. */
+
+static void
+find_identical_ends (filevec)
+     struct file_data filevec[];
+{
+  word *w0, *w1;
+  char *p0, *p1, *buffer0, *buffer1;
+  char const *end0, *beg0;
+  char const **linbuf0, **linbuf1;
+  int i, lines;
+  size_t n0, n1, tem;
+  int alloc_lines0, alloc_lines1;
+  int buffered_prefix, prefix_count, prefix_mask;
+
+  slurp (&filevec[0]);
+  if (filevec[0].desc != filevec[1].desc)
+    slurp (&filevec[1]);
+  else
+    {
+      filevec[1].buffer = filevec[0].buffer;
+      filevec[1].bufsize = filevec[0].bufsize;
+      filevec[1].buffered_chars = filevec[0].buffered_chars;
+    }
+  for (i = 0; i < 2; i++)
+    prepare_text_end (&filevec[i]);
+
+  /* Find identical prefix.  */
+
+  p0 = buffer0 = filevec[0].buffer;
+  p1 = buffer1 = filevec[1].buffer;
+
+  n0 = filevec[0].buffered_chars;
+  n1 = filevec[1].buffered_chars;
+
+  if (p0 == p1)
+    /* The buffers are the same; sentinels won't work.  */
+    p0 = p1 += n1;
+  else
+    {
+      /* Insert end sentinels, in this case characters that are guaranteed
+	 to make the equality test false, and thus terminate the loop.  */
+
+      if (n0 < n1)
+	p0[n0] = ~p1[n0];
+      else
+	p1[n1] = ~p0[n1];
+
+      /* Loop until first mismatch, or to the sentinel characters.  */
+
+      /* Compare a word at a time for speed.  */
+      w0 = (word *) p0;
+      w1 = (word *) p1;
+      while (*w0++ == *w1++)
+	;
+      --w0, --w1;
+
+      /* Do the last few bytes of comparison a byte at a time.  */
+      p0 = (char *) w0;
+      p1 = (char *) w1;
+      while (*p0++ == *p1++)
+	;
+      --p0, --p1;
+
+      /* Don't mistakenly count missing newline as part of prefix. */
+      if (ROBUST_OUTPUT_STYLE (output_style)
+	  && (buffer0 + n0 - filevec[0].missing_newline < p0)
+	     !=
+	     (buffer1 + n1 - filevec[1].missing_newline < p1))
+	--p0, --p1;
+    }
+
+  /* Now P0 and P1 point at the first nonmatching characters.  */
+
+  /* Skip back to last line-beginning in the prefix,
+     and then discard up to HORIZON_LINES lines from the prefix.  */
+  i = horizon_lines;
+  while (p0 != buffer0 && (p0[-1] != '\n' || i--))
+    --p0, --p1;
+
+  /* Record the prefix.  */
+  filevec[0].prefix_end = p0;
+  filevec[1].prefix_end = p1;
+
+  /* Find identical suffix.  */
+
+  /* P0 and P1 point beyond the last chars not yet compared.  */
+  p0 = buffer0 + n0;
+  p1 = buffer1 + n1;
+
+  if (! ROBUST_OUTPUT_STYLE (output_style)
+      || filevec[0].missing_newline == filevec[1].missing_newline)
+    {
+      end0 = p0;	/* Addr of last char in file 0.  */
+
+      /* Get value of P0 at which we should stop scanning backward:
+	 this is when either P0 or P1 points just past the last char
+	 of the identical prefix.  */
+      beg0 = filevec[0].prefix_end + (n0 < n1 ? 0 : n0 - n1);
+
+      /* Scan back until chars don't match or we reach that point.  */
+      while (p0 != beg0)
+	if (*--p0 != *--p1)
+	  {
+	    /* Point at the first char of the matching suffix.  */
+	    ++p0, ++p1;
+	    beg0 = p0;
+	    break;
+	  }
+
+      /* Are we at a line-beginning in both files?  If not, add the rest of
+	 this line to the main body.  Discard up to HORIZON_LINES lines from
+	 the identical suffix.  Also, discard one extra line,
+	 because shift_boundaries may need it.  */
+      i = horizon_lines + !((buffer0 == p0 || p0[-1] == '\n')
+			    &&
+			    (buffer1 == p1 || p1[-1] == '\n'));
+      while (i-- && p0 != end0)
+	while (*p0++ != '\n')
+	  ;
+
+      p1 += p0 - beg0;
+    }
+
+  /* Record the suffix.  */
+  filevec[0].suffix_begin = p0;
+  filevec[1].suffix_begin = p1;
+
+  /* Calculate number of lines of prefix to save.
+
+     prefix_count == 0 means save the whole prefix;
+     we need this with for options like -D that output the whole file.
+     We also need it for options like -F that output some preceding line;
+     at least we will need to find the last few lines,
+     but since we don't know how many, it's easiest to find them all.
+
+     Otherwise, prefix_count != 0.  Save just prefix_count lines at start
+     of the line buffer; they'll be moved to the proper location later.
+     Handle 1 more line than the context says (because we count 1 too many),
+     rounded up to the next power of 2 to speed index computation.  */
+
+  if (no_diff_means_no_output && ! function_regexp_list)
+    {
+      for (prefix_count = 1;  prefix_count < context + 1;  prefix_count *= 2)
+	;
+      prefix_mask = prefix_count - 1;
+      alloc_lines0
+	= prefix_count
+	  + GUESS_LINES (0, 0, p0 - filevec[0].prefix_end)
+	  + context;
+    }
+  else
+    {
+      prefix_count = 0;
+      prefix_mask = ~0;
+      alloc_lines0 = GUESS_LINES (0, 0, n0);
+    }
+
+  lines = 0;
+  linbuf0 = (char const **) xmalloc (alloc_lines0 * sizeof (*linbuf0));
+
+  /* If the prefix is needed, find the prefix lines.  */
+  if (! (no_diff_means_no_output
+	 && filevec[0].prefix_end == p0
+	 && filevec[1].prefix_end == p1))
+    {
+      p0 = buffer0;
+      end0 = filevec[0].prefix_end;
+      while (p0 != end0)
+	{
+	  int l = lines++ & prefix_mask;
+	  if (l == alloc_lines0)
+	    linbuf0 = (char const **) xrealloc (linbuf0, (alloc_lines0 *= 2)
+							 * sizeof(*linbuf0));
+	  linbuf0[l] = p0;
+	  while (*p0++ != '\n')
+	    ;
+	}
+    }
+  buffered_prefix = prefix_count && context < lines ? context : lines;
+
+  /* Allocate line buffer 1.  */
+  tem = prefix_count ? filevec[1].suffix_begin - buffer1 : n1;
+
+  alloc_lines1
+    = (buffered_prefix
+       + GUESS_LINES (lines, filevec[1].prefix_end - buffer1, tem)
+       + context);
+  linbuf1 = (char const **) xmalloc (alloc_lines1 * sizeof (*linbuf1));
+
+  if (buffered_prefix != lines)
+    {
+      /* Rotate prefix lines to proper location.  */
+      for (i = 0;  i < buffered_prefix;  i++)
+	linbuf1[i] = linbuf0[(lines - context + i) & prefix_mask];
+      for (i = 0;  i < buffered_prefix;  i++)
+	linbuf0[i] = linbuf1[i];
+    }
+
+  /* Initialize line buffer 1 from line buffer 0.  */
+  for (i = 0; i < buffered_prefix; i++)
+    linbuf1[i] = linbuf0[i] - buffer0 + buffer1;
+
+  /* Record the line buffer, adjusted so that
+     linbuf*[0] points at the first differing line.  */
+  filevec[0].linbuf = linbuf0 + buffered_prefix;
+  filevec[1].linbuf = linbuf1 + buffered_prefix;
+  filevec[0].linbuf_base = filevec[1].linbuf_base = - buffered_prefix;
+  filevec[0].alloc_lines = alloc_lines0 - buffered_prefix;
+  filevec[1].alloc_lines = alloc_lines1 - buffered_prefix;
+  filevec[0].prefix_lines = filevec[1].prefix_lines = lines;
+}
+
+/* Largest primes less than some power of two, for nbuckets.  Values range
+   from useful to preposterous.  If one of these numbers isn't prime
+   after all, don't blame it on me, blame it on primes (6) . . . */
+static int const primes[] =
+{
+  509,
+  1021,
+  2039,
+  4093,
+  8191,
+  16381,
+  32749,
+#if 32767 < INT_MAX
+  65521,
+  131071,
+  262139,
+  524287,
+  1048573,
+  2097143,
+  4194301,
+  8388593,
+  16777213,
+  33554393,
+  67108859,			/* Preposterously large . . . */
+  134217689,
+  268435399,
+  536870909,
+  1073741789,
+  2147483647,
+#endif
+  0
+};
+
+/* Given a vector of two file_data objects, read the file associated
+   with each one, and build the table of equivalence classes.
+   Return 1 if either file appears to be a binary file.
+   If PRETEND_BINARY is nonzero, pretend they are binary regardless.  */
+
+int
+read_files (filevec, pretend_binary)
+     struct file_data filevec[];
+     int pretend_binary;
+{
+  int i;
+  int skip_test = always_text_flag | pretend_binary;
+  int appears_binary = pretend_binary | sip (&filevec[0], skip_test);
+
+  if (filevec[0].desc != filevec[1].desc)
+    appears_binary |= sip (&filevec[1], skip_test | appears_binary);
+  else
+    {
+      filevec[1].buffer = filevec[0].buffer;
+      filevec[1].bufsize = filevec[0].bufsize;
+      filevec[1].buffered_chars = filevec[0].buffered_chars;
+    }
+  if (appears_binary)
+    {
+#if HAVE_SETMODE
+      setmode (filevec[0].desc, O_BINARY);
+      setmode (filevec[1].desc, O_BINARY);
+#endif
+      return 1;
+    }
+
+  find_identical_ends (filevec);
+
+  equivs_alloc = filevec[0].alloc_lines + filevec[1].alloc_lines + 1;
+  equivs = (struct equivclass *) xmalloc (equivs_alloc * sizeof (struct equivclass));
+  /* Equivalence class 0 is permanently safe for lines that were not
+     hashed.  Real equivalence classes start at 1. */
+  equivs_index = 1;
+
+  for (i = 0;  primes[i] < equivs_alloc / 3;  i++)
+    if (! primes[i])
+      abort ();
+  nbuckets = primes[i];
+
+  buckets = (int *) xmalloc ((nbuckets + 1) * sizeof (*buckets));
+  bzero (buckets++, (nbuckets + 1) * sizeof (*buckets));
+
+  for (i = 0; i < 2; i++)
+    find_and_hash_each_line (&filevec[i]);
+
+  filevec[0].equiv_max = filevec[1].equiv_max = equivs_index;
+
+  free (equivs);
+  free (buckets - 1);
+
+  return 0;
+}
diff --git a/gnu/usr.bin/diff/normal.c b/gnu/usr.bin/diff/normal.c
new file mode 100644
index 00000000000..4d9e23cb72a
--- /dev/null
+++ b/gnu/usr.bin/diff/normal.c
@@ -0,0 +1,71 @@
+/* Normal-format output routines for GNU DIFF.
+   Copyright (C) 1988, 1989, 1993 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+
+#include "diff.h"
+
+static void print_normal_hunk PARAMS((struct change *));
+
+/* Print the edit-script SCRIPT as a normal diff.
+   INF points to an array of descriptions of the two files.  */
+
+void
+print_normal_script (script)
+     struct change *script;
+{
+  print_script (script, find_change, print_normal_hunk);
+}
+
+/* Print a hunk of a normal diff.
+   This is a contiguous portion of a complete edit script,
+   describing changes in consecutive lines.  */
+
+static void
+print_normal_hunk (hunk)
+     struct change *hunk;
+{
+  int first0, last0, first1, last1, deletes, inserts;
+  register int i;
+
+  /* Determine range of line numbers involved in each file.  */
+  analyze_hunk (hunk, &first0, &last0, &first1, &last1, &deletes, &inserts);
+  if (!deletes && !inserts)
+    return;
+
+  begin_output ();
+
+  /* Print out the line number header for this hunk */
+  print_number_range (',', &files[0], first0, last0);
+  fprintf (outfile, "%c", change_letter (inserts, deletes));
+  print_number_range (',', &files[1], first1, last1);
+  fprintf (outfile, "\n");
+
+  /* Print the lines that the first file has.  */
+  if (deletes)
+    for (i = first0; i <= last0; i++)
+      print_1_line ("<", &files[0].linbuf[i]);
+
+  if (inserts && deletes)
+    fprintf (outfile, "---\n");
+
+  /* Print the lines that the second file has.  */
+  if (inserts)
+    for (i = first1; i <= last1; i++)
+      print_1_line (">", &files[1].linbuf[i]);
+}
diff --git a/gnu/usr.bin/diff/regex.c b/gnu/usr.bin/diff/regex.c
new file mode 100644
index 00000000000..5d8c4566f5f
--- /dev/null
+++ b/gnu/usr.bin/diff/regex.c
@@ -0,0 +1,5248 @@
+/* Extended regular expression matching and search library,
+   version 0.12.
+   (Implements POSIX draft P10003.2/D11.2, except for
+   internationalization features.)
+
+   Copyright (C) 1993, 1994 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* AIX requires this to be the first thing in the file. */
+#if defined (_AIX) && !defined (REGEX_MALLOC)
+  #pragma alloca
+#endif
+
+#define _GNU_SOURCE
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+/* We need this for `regex.h', and perhaps for the Emacs include files.  */
+#include <sys/types.h>
+
+/* The `emacs' switch turns on certain matching commands
+   that make sense only in Emacs. */
+#ifdef emacs
+
+#include "lisp.h"
+#include "buffer.h"
+#include "syntax.h"
+
+/* Emacs uses `NULL' as a predicate.  */
+#undef NULL
+
+#else  /* not emacs */
+
+#ifdef STDC_HEADERS
+#include <stdlib.h>
+#else
+char *malloc ();
+char *realloc ();
+#endif
+
+
+/* We used to test for `BSTRING' here, but only GCC and Emacs define
+   `BSTRING', as far as I know, and neither of them use this code.  */
+#ifndef INHIBIT_STRING_HEADER
+#if HAVE_STRING_H || STDC_HEADERS
+#include <string.h>
+#ifndef bcmp
+#define bcmp(s1, s2, n)	memcmp ((s1), (s2), (n))
+#endif
+#ifndef bcopy
+#define bcopy(s, d, n)	memcpy ((d), (s), (n))
+#endif
+#ifndef bzero
+#define bzero(s, n)	memset ((s), 0, (n))
+#endif
+#else
+#include <strings.h>
+#endif
+#endif
+
+/* Define the syntax stuff for \<, \>, etc.  */
+
+/* This must be nonzero for the wordchar and notwordchar pattern
+   commands in re_match_2.  */
+#ifndef Sword 
+#define Sword 1
+#endif
+
+#ifdef SYNTAX_TABLE
+
+extern char *re_syntax_table;
+
+#else /* not SYNTAX_TABLE */
+
+/* How many characters in the character set.  */
+#define CHAR_SET_SIZE 256
+
+static char re_syntax_table[CHAR_SET_SIZE];
+
+static void
+init_syntax_once ()
+{
+   register int c;
+   static int done = 0;
+
+   if (done)
+     return;
+
+   bzero (re_syntax_table, sizeof re_syntax_table);
+
+   for (c = 'a'; c <= 'z'; c++)
+     re_syntax_table[c] = Sword;
+
+   for (c = 'A'; c <= 'Z'; c++)
+     re_syntax_table[c] = Sword;
+
+   for (c = '0'; c <= '9'; c++)
+     re_syntax_table[c] = Sword;
+
+   re_syntax_table['_'] = Sword;
+
+   done = 1;
+}
+
+#endif /* not SYNTAX_TABLE */
+
+#define SYNTAX(c) re_syntax_table[c]
+
+#endif /* not emacs */
+
+/* Get the interface, including the syntax bits.  */
+#include "regex.h"
+
+/* isalpha etc. are used for the character classes.  */
+#include <ctype.h>
+
+/* Jim Meyering writes:
+
+   "... Some ctype macros are valid only for character codes that
+   isascii says are ASCII (SGI's IRIX-4.0.5 is one such system --when
+   using /bin/cc or gcc but without giving an ansi option).  So, all
+   ctype uses should be through macros like ISPRINT...  If
+   STDC_HEADERS is defined, then autoconf has verified that the ctype
+   macros don't need to be guarded with references to isascii. ...
+   Defining isascii to 1 should let any compiler worth its salt
+   eliminate the && through constant folding."  */
+
+#if defined (STDC_HEADERS) || (!defined (isascii) && !defined (HAVE_ISASCII))
+#define ISASCII(c) 1
+#else
+#define ISASCII(c) isascii(c)
+#endif
+
+#ifdef isblank
+#define ISBLANK(c) (ISASCII (c) && isblank (c))
+#else
+#define ISBLANK(c) ((c) == ' ' || (c) == '\t')
+#endif
+#ifdef isgraph
+#define ISGRAPH(c) (ISASCII (c) && isgraph (c))
+#else
+#define ISGRAPH(c) (ISASCII (c) && isprint (c) && !isspace (c))
+#endif
+
+#define ISPRINT(c) (ISASCII (c) && isprint (c))
+#define ISDIGIT(c) (ISASCII (c) && isdigit (c))
+#define ISALNUM(c) (ISASCII (c) && isalnum (c))
+#define ISALPHA(c) (ISASCII (c) && isalpha (c))
+#define ISCNTRL(c) (ISASCII (c) && iscntrl (c))
+#define ISLOWER(c) (ISASCII (c) && islower (c))
+#define ISPUNCT(c) (ISASCII (c) && ispunct (c))
+#define ISSPACE(c) (ISASCII (c) && isspace (c))
+#define ISUPPER(c) (ISASCII (c) && isupper (c))
+#define ISXDIGIT(c) (ISASCII (c) && isxdigit (c))
+
+#ifndef NULL
+#define NULL 0
+#endif
+
+/* We remove any previous definition of `SIGN_EXTEND_CHAR',
+   since ours (we hope) works properly with all combinations of
+   machines, compilers, `char' and `unsigned char' argument types.
+   (Per Bothner suggested the basic approach.)  */
+#undef SIGN_EXTEND_CHAR
+#if __STDC__
+#define SIGN_EXTEND_CHAR(c) ((signed char) (c))
+#else  /* not __STDC__ */
+/* As in Harbison and Steele.  */
+#define SIGN_EXTEND_CHAR(c) ((((unsigned char) (c)) ^ 128) - 128)
+#endif
+
+/* Should we use malloc or alloca?  If REGEX_MALLOC is not defined, we
+   use `alloca' instead of `malloc'.  This is because using malloc in
+   re_search* or re_match* could cause memory leaks when C-g is used in
+   Emacs; also, malloc is slower and causes storage fragmentation.  On
+   the other hand, malloc is more portable, and easier to debug.  
+   
+   Because we sometimes use alloca, some routines have to be macros,
+   not functions -- `alloca'-allocated space disappears at the end of the
+   function it is called in.  */
+
+#ifdef REGEX_MALLOC
+
+#define REGEX_ALLOCATE malloc
+#define REGEX_REALLOCATE(source, osize, nsize) realloc (source, nsize)
+
+#else /* not REGEX_MALLOC  */
+
+/* Emacs already defines alloca, sometimes.  */
+#ifndef alloca
+
+/* Make alloca work the best possible way.  */
+#ifdef __GNUC__
+#define alloca __builtin_alloca
+#else /* not __GNUC__ */
+#if HAVE_ALLOCA_H
+#include <alloca.h>
+#else /* not __GNUC__ or HAVE_ALLOCA_H */
+#ifndef _AIX /* Already did AIX, up at the top.  */
+char *alloca ();
+#endif /* not _AIX */
+#endif /* not HAVE_ALLOCA_H */ 
+#endif /* not __GNUC__ */
+
+#endif /* not alloca */
+
+#define REGEX_ALLOCATE alloca
+
+/* Assumes a `char *destination' variable.  */
+#define REGEX_REALLOCATE(source, osize, nsize)				\
+  (destination = (char *) alloca (nsize),				\
+   bcopy (source, destination, osize),					\
+   destination)
+
+#endif /* not REGEX_MALLOC */
+
+
+/* True if `size1' is non-NULL and PTR is pointing anywhere inside
+   `string1' or just past its end.  This works if PTR is NULL, which is
+   a good thing.  */
+#define FIRST_STRING_P(ptr) 					\
+  (size1 && string1 <= (ptr) && (ptr) <= string1 + size1)
+
+/* (Re)Allocate N items of type T using malloc, or fail.  */
+#define TALLOC(n, t) ((t *) malloc ((n) * sizeof (t)))
+#define RETALLOC(addr, n, t) ((addr) = (t *) realloc (addr, (n) * sizeof (t)))
+#define RETALLOC_IF(addr, n, t) \
+  if (addr) RETALLOC((addr), (n), t); else (addr) = TALLOC ((n), t)
+#define REGEX_TALLOC(n, t) ((t *) REGEX_ALLOCATE ((n) * sizeof (t)))
+
+#define BYTEWIDTH 8 /* In bits.  */
+
+#define STREQ(s1, s2) ((strcmp (s1, s2) == 0))
+
+#undef MAX
+#undef MIN
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+
+typedef char boolean;
+#define false 0
+#define true 1
+
+static int re_match_2_internal ();
+
+/* These are the command codes that appear in compiled regular
+   expressions.  Some opcodes are followed by argument bytes.  A
+   command code can specify any interpretation whatsoever for its
+   arguments.  Zero bytes may appear in the compiled regular expression.
+
+   The value of `exactn' is needed in search.c (search_buffer) in Emacs.
+   So regex.h defines a symbol `RE_EXACTN_VALUE' to be 1; the value of
+   `exactn' we use here must also be 1.  */
+
+typedef enum
+{
+  no_op = 0,
+
+        /* Followed by one byte giving n, then by n literal bytes.  */
+  exactn = 1,
+
+        /* Matches any (more or less) character.  */
+  anychar,
+
+        /* Matches any one char belonging to specified set.  First
+           following byte is number of bitmap bytes.  Then come bytes
+           for a bitmap saying which chars are in.  Bits in each byte
+           are ordered low-bit-first.  A character is in the set if its
+           bit is 1.  A character too large to have a bit in the map is
+           automatically not in the set.  */
+  charset,
+
+        /* Same parameters as charset, but match any character that is
+           not one of those specified.  */
+  charset_not,
+
+        /* Start remembering the text that is matched, for storing in a
+           register.  Followed by one byte with the register number, in
+           the range 0 to one less than the pattern buffer's re_nsub
+           field.  Then followed by one byte with the number of groups
+           inner to this one.  (This last has to be part of the
+           start_memory only because we need it in the on_failure_jump
+           of re_match_2.)  */
+  start_memory,
+
+        /* Stop remembering the text that is matched and store it in a
+           memory register.  Followed by one byte with the register
+           number, in the range 0 to one less than `re_nsub' in the
+           pattern buffer, and one byte with the number of inner groups,
+           just like `start_memory'.  (We need the number of inner
+           groups here because we don't have any easy way of finding the
+           corresponding start_memory when we're at a stop_memory.)  */
+  stop_memory,
+
+        /* Match a duplicate of something remembered. Followed by one
+           byte containing the register number.  */
+  duplicate,
+
+        /* Fail unless at beginning of line.  */
+  begline,
+
+        /* Fail unless at end of line.  */
+  endline,
+
+        /* Succeeds if at beginning of buffer (if emacs) or at beginning
+           of string to be matched (if not).  */
+  begbuf,
+
+        /* Analogously, for end of buffer/string.  */
+  endbuf,
+ 
+        /* Followed by two byte relative address to which to jump.  */
+  jump, 
+
+	/* Same as jump, but marks the end of an alternative.  */
+  jump_past_alt,
+
+        /* Followed by two-byte relative address of place to resume at
+           in case of failure.  */
+  on_failure_jump,
+	
+        /* Like on_failure_jump, but pushes a placeholder instead of the
+           current string position when executed.  */
+  on_failure_keep_string_jump,
+  
+        /* Throw away latest failure point and then jump to following
+           two-byte relative address.  */
+  pop_failure_jump,
+
+        /* Change to pop_failure_jump if know won't have to backtrack to
+           match; otherwise change to jump.  This is used to jump
+           back to the beginning of a repeat.  If what follows this jump
+           clearly won't match what the repeat does, such that we can be
+           sure that there is no use backtracking out of repetitions
+           already matched, then we change it to a pop_failure_jump.
+           Followed by two-byte address.  */
+  maybe_pop_jump,
+
+        /* Jump to following two-byte address, and push a dummy failure
+           point. This failure point will be thrown away if an attempt
+           is made to use it for a failure.  A `+' construct makes this
+           before the first repeat.  Also used as an intermediary kind
+           of jump when compiling an alternative.  */
+  dummy_failure_jump,
+
+	/* Push a dummy failure point and continue.  Used at the end of
+	   alternatives.  */
+  push_dummy_failure,
+
+        /* Followed by two-byte relative address and two-byte number n.
+           After matching N times, jump to the address upon failure.  */
+  succeed_n,
+
+        /* Followed by two-byte relative address, and two-byte number n.
+           Jump to the address N times, then fail.  */
+  jump_n,
+
+        /* Set the following two-byte relative address to the
+           subsequent two-byte number.  The address *includes* the two
+           bytes of number.  */
+  set_number_at,
+
+  wordchar,	/* Matches any word-constituent character.  */
+  notwordchar,	/* Matches any char that is not a word-constituent.  */
+
+  wordbeg,	/* Succeeds if at word beginning.  */
+  wordend,	/* Succeeds if at word end.  */
+
+  wordbound,	/* Succeeds if at a word boundary.  */
+  notwordbound	/* Succeeds if not at a word boundary.  */
+
+#ifdef emacs
+  ,before_dot,	/* Succeeds if before point.  */
+  at_dot,	/* Succeeds if at point.  */
+  after_dot,	/* Succeeds if after point.  */
+
+	/* Matches any character whose syntax is specified.  Followed by
+           a byte which contains a syntax code, e.g., Sword.  */
+  syntaxspec,
+
+	/* Matches any character whose syntax is not that specified.  */
+  notsyntaxspec
+#endif /* emacs */
+} re_opcode_t;
+
+/* Common operations on the compiled pattern.  */
+
+/* Store NUMBER in two contiguous bytes starting at DESTINATION.  */
+
+#define STORE_NUMBER(destination, number)				\
+  do {									\
+    (destination)[0] = (number) & 0377;					\
+    (destination)[1] = (number) >> 8;					\
+  } while (0)
+
+/* Same as STORE_NUMBER, except increment DESTINATION to
+   the byte after where the number is stored.  Therefore, DESTINATION
+   must be an lvalue.  */
+
+#define STORE_NUMBER_AND_INCR(destination, number)			\
+  do {									\
+    STORE_NUMBER (destination, number);					\
+    (destination) += 2;							\
+  } while (0)
+
+/* Put into DESTINATION a number stored in two contiguous bytes starting
+   at SOURCE.  */
+
+#define EXTRACT_NUMBER(destination, source)				\
+  do {									\
+    (destination) = *(source) & 0377;					\
+    (destination) += SIGN_EXTEND_CHAR (*((source) + 1)) << 8;		\
+  } while (0)
+
+#ifdef DEBUG
+static void
+extract_number (dest, source)
+    int *dest;
+    unsigned char *source;
+{
+  int temp = SIGN_EXTEND_CHAR (*(source + 1)); 
+  *dest = *source & 0377;
+  *dest += temp << 8;
+}
+
+#ifndef EXTRACT_MACROS /* To debug the macros.  */
+#undef EXTRACT_NUMBER
+#define EXTRACT_NUMBER(dest, src) extract_number (&dest, src)
+#endif /* not EXTRACT_MACROS */
+
+#endif /* DEBUG */
+
+/* Same as EXTRACT_NUMBER, except increment SOURCE to after the number.
+   SOURCE must be an lvalue.  */
+
+#define EXTRACT_NUMBER_AND_INCR(destination, source)			\
+  do {									\
+    EXTRACT_NUMBER (destination, source);				\
+    (source) += 2; 							\
+  } while (0)
+
+#ifdef DEBUG
+static void
+extract_number_and_incr (destination, source)
+    int *destination;
+    unsigned char **source;
+{ 
+  extract_number (destination, *source);
+  *source += 2;
+}
+
+#ifndef EXTRACT_MACROS
+#undef EXTRACT_NUMBER_AND_INCR
+#define EXTRACT_NUMBER_AND_INCR(dest, src) \
+  extract_number_and_incr (&dest, &src)
+#endif /* not EXTRACT_MACROS */
+
+#endif /* DEBUG */
+
+/* If DEBUG is defined, Regex prints many voluminous messages about what
+   it is doing (if the variable `debug' is nonzero).  If linked with the
+   main program in `iregex.c', you can enter patterns and strings
+   interactively.  And if linked with the main program in `main.c' and
+   the other test files, you can run the already-written tests.  */
+
+#ifdef DEBUG
+
+/* We use standard I/O for debugging.  */
+#include <stdio.h>
+
+/* It is useful to test things that ``must'' be true when debugging.  */
+#include <assert.h>
+
+static int debug = 0;
+
+#define DEBUG_STATEMENT(e) e
+#define DEBUG_PRINT1(x) if (debug) printf (x)
+#define DEBUG_PRINT2(x1, x2) if (debug) printf (x1, x2)
+#define DEBUG_PRINT3(x1, x2, x3) if (debug) printf (x1, x2, x3)
+#define DEBUG_PRINT4(x1, x2, x3, x4) if (debug) printf (x1, x2, x3, x4)
+#define DEBUG_PRINT_COMPILED_PATTERN(p, s, e) 				\
+  if (debug) print_partial_compiled_pattern (s, e)
+#define DEBUG_PRINT_DOUBLE_STRING(w, s1, sz1, s2, sz2)			\
+  if (debug) print_double_string (w, s1, sz1, s2, sz2)
+
+
+extern void printchar ();
+
+/* Print the fastmap in human-readable form.  */
+
+void
+print_fastmap (fastmap)
+    char *fastmap;
+{
+  unsigned was_a_range = 0;
+  unsigned i = 0;  
+  
+  while (i < (1 << BYTEWIDTH))
+    {
+      if (fastmap[i++])
+	{
+	  was_a_range = 0;
+          printchar (i - 1);
+          while (i < (1 << BYTEWIDTH)  &&  fastmap[i])
+            {
+              was_a_range = 1;
+              i++;
+            }
+	  if (was_a_range)
+            {
+              printf ("-");
+              printchar (i - 1);
+            }
+        }
+    }
+  putchar ('\n'); 
+}
+
+
+/* Print a compiled pattern string in human-readable form, starting at
+   the START pointer into it and ending just before the pointer END.  */
+
+void
+print_partial_compiled_pattern (start, end)
+    unsigned char *start;
+    unsigned char *end;
+{
+  int mcnt, mcnt2;
+  unsigned char *p = start;
+  unsigned char *pend = end;
+
+  if (start == NULL)
+    {
+      printf ("(null)\n");
+      return;
+    }
+    
+  /* Loop over pattern commands.  */
+  while (p < pend)
+    {
+      printf ("%d:\t", p - start);
+
+      switch ((re_opcode_t) *p++)
+	{
+        case no_op:
+          printf ("/no_op");
+          break;
+
+	case exactn:
+	  mcnt = *p++;
+          printf ("/exactn/%d", mcnt);
+          do
+	    {
+              putchar ('/');
+	      printchar (*p++);
+            }
+          while (--mcnt);
+          break;
+
+	case start_memory:
+          mcnt = *p++;
+          printf ("/start_memory/%d/%d", mcnt, *p++);
+          break;
+
+	case stop_memory:
+          mcnt = *p++;
+	  printf ("/stop_memory/%d/%d", mcnt, *p++);
+          break;
+
+	case duplicate:
+	  printf ("/duplicate/%d", *p++);
+	  break;
+
+	case anychar:
+	  printf ("/anychar");
+	  break;
+
+	case charset:
+        case charset_not:
+          {
+            register int c, last = -100;
+	    register int in_range = 0;
+
+	    printf ("/charset [%s",
+	            (re_opcode_t) *(p - 1) == charset_not ? "^" : "");
+            
+            assert (p + *p < pend);
+
+            for (c = 0; c < 256; c++)
+	      if (c / 8 < *p
+		  && (p[1 + (c/8)] & (1 << (c % 8))))
+		{
+		  /* Are we starting a range?  */
+		  if (last + 1 == c && ! in_range)
+		    {
+		      putchar ('-');
+		      in_range = 1;
+		    }
+		  /* Have we broken a range?  */
+		  else if (last + 1 != c && in_range)
+              {
+		      printchar (last);
+		      in_range = 0;
+		    }
+                
+		  if (! in_range)
+		    printchar (c);
+
+		  last = c;
+              }
+
+	    if (in_range)
+	      printchar (last);
+
+	    putchar (']');
+
+	    p += 1 + *p;
+	  }
+	  break;
+
+	case begline:
+	  printf ("/begline");
+          break;
+
+	case endline:
+          printf ("/endline");
+          break;
+
+	case on_failure_jump:
+          extract_number_and_incr (&mcnt, &p);
+  	  printf ("/on_failure_jump to %d", p + mcnt - start);
+          break;
+
+	case on_failure_keep_string_jump:
+          extract_number_and_incr (&mcnt, &p);
+  	  printf ("/on_failure_keep_string_jump to %d", p + mcnt - start);
+          break;
+
+	case dummy_failure_jump:
+          extract_number_and_incr (&mcnt, &p);
+  	  printf ("/dummy_failure_jump to %d", p + mcnt - start);
+          break;
+
+	case push_dummy_failure:
+          printf ("/push_dummy_failure");
+          break;
+          
+        case maybe_pop_jump:
+          extract_number_and_incr (&mcnt, &p);
+  	  printf ("/maybe_pop_jump to %d", p + mcnt - start);
+	  break;
+
+        case pop_failure_jump:
+	  extract_number_and_incr (&mcnt, &p);
+  	  printf ("/pop_failure_jump to %d", p + mcnt - start);
+	  break;          
+          
+        case jump_past_alt:
+	  extract_number_and_incr (&mcnt, &p);
+  	  printf ("/jump_past_alt to %d", p + mcnt - start);
+	  break;          
+          
+        case jump:
+	  extract_number_and_incr (&mcnt, &p);
+  	  printf ("/jump to %d", p + mcnt - start);
+	  break;
+
+        case succeed_n: 
+          extract_number_and_incr (&mcnt, &p);
+          extract_number_and_incr (&mcnt2, &p);
+	  printf ("/succeed_n to %d, %d times", p + mcnt - start, mcnt2);
+          break;
+        
+        case jump_n: 
+          extract_number_and_incr (&mcnt, &p);
+          extract_number_and_incr (&mcnt2, &p);
+	  printf ("/jump_n to %d, %d times", p + mcnt - start, mcnt2);
+          break;
+        
+        case set_number_at: 
+          extract_number_and_incr (&mcnt, &p);
+          extract_number_and_incr (&mcnt2, &p);
+	  printf ("/set_number_at location %d to %d", p + mcnt - start, mcnt2);
+          break;
+        
+        case wordbound:
+	  printf ("/wordbound");
+	  break;
+
+	case notwordbound:
+	  printf ("/notwordbound");
+          break;
+
+	case wordbeg:
+	  printf ("/wordbeg");
+	  break;
+          
+	case wordend:
+	  printf ("/wordend");
+          
+#ifdef emacs
+	case before_dot:
+	  printf ("/before_dot");
+          break;
+
+	case at_dot:
+	  printf ("/at_dot");
+          break;
+
+	case after_dot:
+	  printf ("/after_dot");
+          break;
+
+	case syntaxspec:
+          printf ("/syntaxspec");
+	  mcnt = *p++;
+	  printf ("/%d", mcnt);
+          break;
+	  
+	case notsyntaxspec:
+          printf ("/notsyntaxspec");
+	  mcnt = *p++;
+	  printf ("/%d", mcnt);
+	  break;
+#endif /* emacs */
+
+	case wordchar:
+	  printf ("/wordchar");
+          break;
+	  
+	case notwordchar:
+	  printf ("/notwordchar");
+          break;
+
+	case begbuf:
+	  printf ("/begbuf");
+          break;
+
+	case endbuf:
+	  printf ("/endbuf");
+          break;
+
+        default:
+          printf ("?%d", *(p-1));
+	}
+
+      putchar ('\n');
+    }
+
+  printf ("%d:\tend of pattern.\n", p - start);
+}
+
+
+void
+print_compiled_pattern (bufp)
+    struct re_pattern_buffer *bufp;
+{
+  unsigned char *buffer = bufp->buffer;
+
+  print_partial_compiled_pattern (buffer, buffer + bufp->used);
+  printf ("%d bytes used/%d bytes allocated.\n", bufp->used, bufp->allocated);
+
+  if (bufp->fastmap_accurate && bufp->fastmap)
+    {
+      printf ("fastmap: ");
+      print_fastmap (bufp->fastmap);
+    }
+
+  printf ("re_nsub: %d\t", bufp->re_nsub);
+  printf ("regs_alloc: %d\t", bufp->regs_allocated);
+  printf ("can_be_null: %d\t", bufp->can_be_null);
+  printf ("newline_anchor: %d\n", bufp->newline_anchor);
+  printf ("no_sub: %d\t", bufp->no_sub);
+  printf ("not_bol: %d\t", bufp->not_bol);
+  printf ("not_eol: %d\t", bufp->not_eol);
+  printf ("syntax: %d\n", bufp->syntax);
+  /* Perhaps we should print the translate table?  */
+}
+
+
+void
+print_double_string (where, string1, size1, string2, size2)
+    const char *where;
+    const char *string1;
+    const char *string2;
+    int size1;
+    int size2;
+{
+  unsigned this_char;
+  
+  if (where == NULL)
+    printf ("(null)");
+  else
+    {
+      if (FIRST_STRING_P (where))
+        {
+          for (this_char = where - string1; this_char < size1; this_char++)
+            printchar (string1[this_char]);
+
+          where = string2;    
+        }
+
+      for (this_char = where - string2; this_char < size2; this_char++)
+        printchar (string2[this_char]);
+    }
+}
+
+#else /* not DEBUG */
+
+#undef assert
+#define assert(e)
+
+#define DEBUG_STATEMENT(e)
+#define DEBUG_PRINT1(x)
+#define DEBUG_PRINT2(x1, x2)
+#define DEBUG_PRINT3(x1, x2, x3)
+#define DEBUG_PRINT4(x1, x2, x3, x4)
+#define DEBUG_PRINT_COMPILED_PATTERN(p, s, e)
+#define DEBUG_PRINT_DOUBLE_STRING(w, s1, sz1, s2, sz2)
+
+#endif /* not DEBUG */
+
+/* Set by `re_set_syntax' to the current regexp syntax to recognize.  Can
+   also be assigned to arbitrarily: each pattern buffer stores its own
+   syntax, so it can be changed between regex compilations.  */
+reg_syntax_t re_syntax_options = RE_SYNTAX_EMACS;
+
+
+/* Specify the precise syntax of regexps for compilation.  This provides
+   for compatibility for various utilities which historically have
+   different, incompatible syntaxes.
+
+   The argument SYNTAX is a bit mask comprised of the various bits
+   defined in regex.h.  We return the old syntax.  */
+
+reg_syntax_t
+re_set_syntax (syntax)
+    reg_syntax_t syntax;
+{
+  reg_syntax_t ret = re_syntax_options;
+  
+  re_syntax_options = syntax;
+  return ret;
+}
+
+/* This table gives an error message for each of the error codes listed
+   in regex.h.  Obviously the order here has to be same as there.  */
+
+static const char *re_error_msg[] =
+  { NULL,					/* REG_NOERROR */
+    "No match",					/* REG_NOMATCH */
+    "Invalid regular expression",		/* REG_BADPAT */
+    "Invalid collation character",		/* REG_ECOLLATE */
+    "Invalid character class name",		/* REG_ECTYPE */
+    "Trailing backslash",			/* REG_EESCAPE */
+    "Invalid back reference",			/* REG_ESUBREG */
+    "Unmatched [ or [^",			/* REG_EBRACK */
+    "Unmatched ( or \\(",			/* REG_EPAREN */
+    "Unmatched \\{",				/* REG_EBRACE */
+    "Invalid content of \\{\\}",		/* REG_BADBR */
+    "Invalid range end",			/* REG_ERANGE */
+    "Memory exhausted",				/* REG_ESPACE */
+    "Invalid preceding regular expression",	/* REG_BADRPT */
+    "Premature end of regular expression",	/* REG_EEND */
+    "Regular expression too big",		/* REG_ESIZE */
+    "Unmatched ) or \\)",			/* REG_ERPAREN */
+  };
+
+/* Avoiding alloca during matching, to placate r_alloc.  */
+
+/* Define MATCH_MAY_ALLOCATE unless we need to make sure that the
+   searching and matching functions should not call alloca.  On some
+   systems, alloca is implemented in terms of malloc, and if we're
+   using the relocating allocator routines, then malloc could cause a
+   relocation, which might (if the strings being searched are in the
+   ralloc heap) shift the data out from underneath the regexp
+   routines.
+
+   Here's another reason to avoid allocation: Emacs 
+   processes input from X in a signal handler; processing X input may
+   call malloc; if input arrives while a matching routine is calling
+   malloc, then we're scrod.  But Emacs can't just block input while
+   calling matching routines; then we don't notice interrupts when
+   they come in.  So, Emacs blocks input around all regexp calls
+   except the matching calls, which it leaves unprotected, in the
+   faith that they will not malloc.  */
+
+/* Normally, this is fine.  */
+#define MATCH_MAY_ALLOCATE
+
+/* The match routines may not allocate if (1) they would do it with malloc
+   and (2) it's not safe for htem to use malloc.  */
+#if (defined (C_ALLOCA) || defined (REGEX_MALLOC)) && (defined (emacs) || defined (REL_ALLOC))
+#undef MATCH_MAY_ALLOCATE
+#endif
+
+
+/* Failure stack declarations and macros; both re_compile_fastmap and
+   re_match_2 use a failure stack.  These have to be macros because of
+   REGEX_ALLOCATE.  */
+   
+
+/* Number of failure points for which to initially allocate space
+   when matching.  If this number is exceeded, we allocate more
+   space, so it is not a hard limit.  */
+#ifndef INIT_FAILURE_ALLOC
+#define INIT_FAILURE_ALLOC 5
+#endif
+
+/* Roughly the maximum number of failure points on the stack.  Would be
+   exactly that if always used MAX_FAILURE_SPACE each time we failed.
+   This is a variable only so users of regex can assign to it; we never
+   change it ourselves.  */
+int re_max_failures = 2000;
+
+typedef unsigned char *fail_stack_elt_t;
+
+typedef struct
+{
+  fail_stack_elt_t *stack;
+  unsigned size;
+  unsigned avail;			/* Offset of next open position.  */
+} fail_stack_type;
+
+#define FAIL_STACK_EMPTY()     (fail_stack.avail == 0)
+#define FAIL_STACK_PTR_EMPTY() (fail_stack_ptr->avail == 0)
+#define FAIL_STACK_FULL()      (fail_stack.avail == fail_stack.size)
+#define FAIL_STACK_TOP()       (fail_stack.stack[fail_stack.avail])
+
+
+/* Initialize `fail_stack'.  Do `return -2' if the alloc fails.  */
+
+#ifdef MATCH_MAY_ALLOCATE
+#define INIT_FAIL_STACK()						\
+  do {									\
+    fail_stack.stack = (fail_stack_elt_t *)				\
+      REGEX_ALLOCATE (INIT_FAILURE_ALLOC * sizeof (fail_stack_elt_t));	\
+									\
+    if (fail_stack.stack == NULL)					\
+      return -2;							\
+									\
+    fail_stack.size = INIT_FAILURE_ALLOC;				\
+    fail_stack.avail = 0;						\
+  } while (0)
+#else
+#define INIT_FAIL_STACK()						\
+  do {									\
+    fail_stack.avail = 0;						\
+  } while (0)
+#endif
+
+
+/* Double the size of FAIL_STACK, up to approximately `re_max_failures' items.
+
+   Return 1 if succeeds, and 0 if either ran out of memory
+   allocating space for it or it was already too large.  
+   
+   REGEX_REALLOCATE requires `destination' be declared.   */
+
+#define DOUBLE_FAIL_STACK(fail_stack)					\
+  ((fail_stack).size > re_max_failures * MAX_FAILURE_ITEMS		\
+   ? 0									\
+   : ((fail_stack).stack = (fail_stack_elt_t *)				\
+        REGEX_REALLOCATE ((fail_stack).stack, 				\
+          (fail_stack).size * sizeof (fail_stack_elt_t),		\
+          ((fail_stack).size << 1) * sizeof (fail_stack_elt_t)),	\
+									\
+      (fail_stack).stack == NULL					\
+      ? 0								\
+      : ((fail_stack).size <<= 1, 					\
+         1)))
+
+
+/* Push PATTERN_OP on FAIL_STACK. 
+
+   Return 1 if was able to do so and 0 if ran out of memory allocating
+   space to do so.  */
+#define PUSH_PATTERN_OP(pattern_op, fail_stack)				\
+  ((FAIL_STACK_FULL ()							\
+    && !DOUBLE_FAIL_STACK (fail_stack))					\
+    ? 0									\
+    : ((fail_stack).stack[(fail_stack).avail++] = pattern_op,		\
+       1))
+
+/* This pushes an item onto the failure stack.  Must be a four-byte
+   value.  Assumes the variable `fail_stack'.  Probably should only
+   be called from within `PUSH_FAILURE_POINT'.  */
+#define PUSH_FAILURE_ITEM(item)						\
+  fail_stack.stack[fail_stack.avail++] = (fail_stack_elt_t) (long) item
+
+/* The complement operation.  Assumes `fail_stack' is nonempty.  */
+#define POP_FAILURE_ITEM() fail_stack.stack[--fail_stack.avail]
+
+/* Used to omit pushing failure point id's when we're not debugging.  */
+#ifdef DEBUG
+#define DEBUG_PUSH PUSH_FAILURE_ITEM
+#define DEBUG_POP(item_addr) *(item_addr) = POP_FAILURE_ITEM ()
+#else
+#define DEBUG_PUSH(item)
+#define DEBUG_POP(item_addr)
+#endif
+
+
+/* Push the information about the state we will need
+   if we ever fail back to it.  
+   
+   Requires variables fail_stack, regstart, regend, reg_info, and
+   num_regs be declared.  DOUBLE_FAIL_STACK requires `destination' be
+   declared.
+   
+   Does `return FAILURE_CODE' if runs out of memory.  */
+
+#define PUSH_FAILURE_POINT(pattern_place, string_place, failure_code)	\
+  do {									\
+    char *destination;							\
+    /* Must be int, so when we don't save any registers, the arithmetic	\
+       of 0 + -1 isn't done as unsigned.  */				\
+    int this_reg;							\
+    									\
+    DEBUG_STATEMENT (failure_id++);					\
+    DEBUG_STATEMENT (nfailure_points_pushed++);				\
+    DEBUG_PRINT2 ("\nPUSH_FAILURE_POINT #%u:\n", failure_id);		\
+    DEBUG_PRINT2 ("  Before push, next avail: %d\n", (fail_stack).avail);\
+    DEBUG_PRINT2 ("                     size: %d\n", (fail_stack).size);\
+									\
+    DEBUG_PRINT2 ("  slots needed: %d\n", NUM_FAILURE_ITEMS);		\
+    DEBUG_PRINT2 ("     available: %d\n", REMAINING_AVAIL_SLOTS);	\
+									\
+    /* Ensure we have enough space allocated for what we will push.  */	\
+    while (REMAINING_AVAIL_SLOTS < NUM_FAILURE_ITEMS)			\
+      {									\
+        if (!DOUBLE_FAIL_STACK (fail_stack))			\
+          return failure_code;						\
+									\
+        DEBUG_PRINT2 ("\n  Doubled stack; size now: %d\n",		\
+		       (fail_stack).size);				\
+        DEBUG_PRINT2 ("  slots available: %d\n", REMAINING_AVAIL_SLOTS);\
+      }									\
+									\
+    /* Push the info, starting with the registers.  */			\
+    DEBUG_PRINT1 ("\n");						\
+									\
+    for (this_reg = lowest_active_reg; this_reg <= highest_active_reg;	\
+         this_reg++)							\
+      {									\
+	DEBUG_PRINT2 ("  Pushing reg: %d\n", this_reg);			\
+        DEBUG_STATEMENT (num_regs_pushed++);				\
+									\
+	DEBUG_PRINT2 ("    start: 0x%x\n", regstart[this_reg]);		\
+        PUSH_FAILURE_ITEM (regstart[this_reg]);				\
+                                                                        \
+	DEBUG_PRINT2 ("    end: 0x%x\n", regend[this_reg]);		\
+        PUSH_FAILURE_ITEM (regend[this_reg]);				\
+									\
+	DEBUG_PRINT2 ("    info: 0x%x\n      ", reg_info[this_reg]);	\
+        DEBUG_PRINT2 (" match_null=%d",					\
+                      REG_MATCH_NULL_STRING_P (reg_info[this_reg]));	\
+        DEBUG_PRINT2 (" active=%d", IS_ACTIVE (reg_info[this_reg]));	\
+        DEBUG_PRINT2 (" matched_something=%d",				\
+                      MATCHED_SOMETHING (reg_info[this_reg]));		\
+        DEBUG_PRINT2 (" ever_matched=%d",				\
+                      EVER_MATCHED_SOMETHING (reg_info[this_reg]));	\
+	DEBUG_PRINT1 ("\n");						\
+        PUSH_FAILURE_ITEM (reg_info[this_reg].word);			\
+      }									\
+									\
+    DEBUG_PRINT2 ("  Pushing  low active reg: %d\n", lowest_active_reg);\
+    PUSH_FAILURE_ITEM (lowest_active_reg);				\
+									\
+    DEBUG_PRINT2 ("  Pushing high active reg: %d\n", highest_active_reg);\
+    PUSH_FAILURE_ITEM (highest_active_reg);				\
+									\
+    DEBUG_PRINT2 ("  Pushing pattern 0x%x: ", pattern_place);		\
+    DEBUG_PRINT_COMPILED_PATTERN (bufp, pattern_place, pend);		\
+    PUSH_FAILURE_ITEM (pattern_place);					\
+									\
+    DEBUG_PRINT2 ("  Pushing string 0x%x: `", string_place);		\
+    DEBUG_PRINT_DOUBLE_STRING (string_place, string1, size1, string2,   \
+				 size2);				\
+    DEBUG_PRINT1 ("'\n");						\
+    PUSH_FAILURE_ITEM (string_place);					\
+									\
+    DEBUG_PRINT2 ("  Pushing failure id: %u\n", failure_id);		\
+    DEBUG_PUSH (failure_id);						\
+  } while (0)
+
+/* This is the number of items that are pushed and popped on the stack
+   for each register.  */
+#define NUM_REG_ITEMS  3
+
+/* Individual items aside from the registers.  */
+#ifdef DEBUG
+#define NUM_NONREG_ITEMS 5 /* Includes failure point id.  */
+#else
+#define NUM_NONREG_ITEMS 4
+#endif
+
+/* We push at most this many items on the stack.  */
+#define MAX_FAILURE_ITEMS ((num_regs - 1) * NUM_REG_ITEMS + NUM_NONREG_ITEMS)
+
+/* We actually push this many items.  */
+#define NUM_FAILURE_ITEMS						\
+  ((highest_active_reg - lowest_active_reg + 1) * NUM_REG_ITEMS 	\
+    + NUM_NONREG_ITEMS)
+
+/* How many items can still be added to the stack without overflowing it.  */
+#define REMAINING_AVAIL_SLOTS ((fail_stack).size - (fail_stack).avail)
+
+
+/* Pops what PUSH_FAIL_STACK pushes.
+
+   We restore into the parameters, all of which should be lvalues:
+     STR -- the saved data position.
+     PAT -- the saved pattern position.
+     LOW_REG, HIGH_REG -- the highest and lowest active registers.
+     REGSTART, REGEND -- arrays of string positions.
+     REG_INFO -- array of information about each subexpression.
+   
+   Also assumes the variables `fail_stack' and (if debugging), `bufp',
+   `pend', `string1', `size1', `string2', and `size2'.  */
+
+#define POP_FAILURE_POINT(str, pat, low_reg, high_reg, regstart, regend, reg_info)\
+{									\
+  DEBUG_STATEMENT (fail_stack_elt_t failure_id;)			\
+  int this_reg;								\
+  const unsigned char *string_temp;					\
+									\
+  assert (!FAIL_STACK_EMPTY ());					\
+									\
+  /* Remove failure points and point to how many regs pushed.  */	\
+  DEBUG_PRINT1 ("POP_FAILURE_POINT:\n");				\
+  DEBUG_PRINT2 ("  Before pop, next avail: %d\n", fail_stack.avail);	\
+  DEBUG_PRINT2 ("                    size: %d\n", fail_stack.size);	\
+									\
+  assert (fail_stack.avail >= NUM_NONREG_ITEMS);			\
+									\
+  DEBUG_POP (&failure_id);						\
+  DEBUG_PRINT2 ("  Popping failure id: %u\n", failure_id);		\
+									\
+  /* If the saved string location is NULL, it came from an		\
+     on_failure_keep_string_jump opcode, and we want to throw away the	\
+     saved NULL, thus retaining our current position in the string.  */	\
+  string_temp = POP_FAILURE_ITEM ();					\
+  if (string_temp != NULL)						\
+    str = (const char *) string_temp;					\
+									\
+  DEBUG_PRINT2 ("  Popping string 0x%x: `", str);			\
+  DEBUG_PRINT_DOUBLE_STRING (str, string1, size1, string2, size2);	\
+  DEBUG_PRINT1 ("'\n");							\
+									\
+  pat = (unsigned char *) POP_FAILURE_ITEM ();				\
+  DEBUG_PRINT2 ("  Popping pattern 0x%x: ", pat);			\
+  DEBUG_PRINT_COMPILED_PATTERN (bufp, pat, pend);			\
+									\
+  /* Restore register info.  */						\
+  high_reg = (unsigned long) POP_FAILURE_ITEM ();			\
+  DEBUG_PRINT2 ("  Popping high active reg: %d\n", high_reg);		\
+									\
+  low_reg = (unsigned long) POP_FAILURE_ITEM ();			\
+  DEBUG_PRINT2 ("  Popping  low active reg: %d\n", low_reg);		\
+									\
+  for (this_reg = high_reg; this_reg >= low_reg; this_reg--)		\
+    {									\
+      DEBUG_PRINT2 ("    Popping reg: %d\n", this_reg);			\
+									\
+      reg_info[this_reg].word = POP_FAILURE_ITEM ();			\
+      DEBUG_PRINT2 ("      info: 0x%x\n", reg_info[this_reg]);		\
+									\
+      regend[this_reg] = (const char *) POP_FAILURE_ITEM ();		\
+      DEBUG_PRINT2 ("      end: 0x%x\n", regend[this_reg]);		\
+									\
+      regstart[this_reg] = (const char *) POP_FAILURE_ITEM ();		\
+      DEBUG_PRINT2 ("      start: 0x%x\n", regstart[this_reg]);		\
+    }									\
+									\
+  DEBUG_STATEMENT (nfailure_points_popped++);				\
+} /* POP_FAILURE_POINT */
+
+
+
+/* Structure for per-register (a.k.a. per-group) information.
+   This must not be longer than one word, because we push this value
+   onto the failure stack.  Other register information, such as the
+   starting and ending positions (which are addresses), and the list of
+   inner groups (which is a bits list) are maintained in separate
+   variables.  
+   
+   We are making a (strictly speaking) nonportable assumption here: that
+   the compiler will pack our bit fields into something that fits into
+   the type of `word', i.e., is something that fits into one item on the
+   failure stack.  */
+typedef union
+{
+  fail_stack_elt_t word;
+  struct
+  {
+      /* This field is one if this group can match the empty string,
+         zero if not.  If not yet determined,  `MATCH_NULL_UNSET_VALUE'.  */
+#define MATCH_NULL_UNSET_VALUE 3
+    unsigned match_null_string_p : 2;
+    unsigned is_active : 1;
+    unsigned matched_something : 1;
+    unsigned ever_matched_something : 1;
+  } bits;
+} register_info_type;
+
+#define REG_MATCH_NULL_STRING_P(R)  ((R).bits.match_null_string_p)
+#define IS_ACTIVE(R)  ((R).bits.is_active)
+#define MATCHED_SOMETHING(R)  ((R).bits.matched_something)
+#define EVER_MATCHED_SOMETHING(R)  ((R).bits.ever_matched_something)
+
+
+/* Call this when have matched a real character; it sets `matched' flags
+   for the subexpressions which we are currently inside.  Also records
+   that those subexprs have matched.  */
+#define SET_REGS_MATCHED()						\
+  do									\
+    {									\
+      unsigned r;							\
+      for (r = lowest_active_reg; r <= highest_active_reg; r++)		\
+        {								\
+          MATCHED_SOMETHING (reg_info[r])				\
+            = EVER_MATCHED_SOMETHING (reg_info[r])			\
+            = 1;							\
+        }								\
+    }									\
+  while (0)
+
+
+/* Registers are set to a sentinel when they haven't yet matched.  */
+#define REG_UNSET_VALUE ((char *) -1)
+#define REG_UNSET(e) ((e) == REG_UNSET_VALUE)
+
+
+
+/* How do we implement a missing MATCH_MAY_ALLOCATE?
+   We make the fail stack a global thing, and then grow it to
+   re_max_failures when we compile.  */
+#ifndef MATCH_MAY_ALLOCATE
+static fail_stack_type fail_stack;
+
+static const char **     regstart, **     regend;
+static const char ** old_regstart, ** old_regend;
+static const char **best_regstart, **best_regend;
+static register_info_type *reg_info; 
+static const char **reg_dummy;
+static register_info_type *reg_info_dummy;
+#endif
+
+
+/* Subroutine declarations and macros for regex_compile.  */
+
+static void store_op1 (), store_op2 ();
+static void insert_op1 (), insert_op2 ();
+static boolean at_begline_loc_p (), at_endline_loc_p ();
+static boolean group_in_compile_stack ();
+static reg_errcode_t compile_range ();
+
+/* Fetch the next character in the uncompiled pattern---translating it 
+   if necessary.  Also cast from a signed character in the constant
+   string passed to us by the user to an unsigned char that we can use
+   as an array index (in, e.g., `translate').  */
+#define PATFETCH(c)							\
+  do {if (p == pend) return REG_EEND;					\
+    c = (unsigned char) *p++;						\
+    if (translate) c = translate[c]; 					\
+  } while (0)
+
+/* Fetch the next character in the uncompiled pattern, with no
+   translation.  */
+#define PATFETCH_RAW(c)							\
+  do {if (p == pend) return REG_EEND;					\
+    c = (unsigned char) *p++; 						\
+  } while (0)
+
+/* Go backwards one character in the pattern.  */
+#define PATUNFETCH p--
+
+
+/* If `translate' is non-null, return translate[D], else just D.  We
+   cast the subscript to translate because some data is declared as
+   `char *', to avoid warnings when a string constant is passed.  But
+   when we use a character as a subscript we must make it unsigned.  */
+#define TRANSLATE(d) (translate ? translate[(unsigned char) (d)] : (d))
+
+
+/* Macros for outputting the compiled pattern into `buffer'.  */
+
+/* If the buffer isn't allocated when it comes in, use this.  */
+#define INIT_BUF_SIZE  32
+
+/* Make sure we have at least N more bytes of space in buffer.  */
+#define GET_BUFFER_SPACE(n)						\
+    while (b - bufp->buffer + (n) > bufp->allocated)			\
+      EXTEND_BUFFER ()
+
+/* Make sure we have one more byte of buffer space and then add C to it.  */
+#define BUF_PUSH(c)							\
+  do {									\
+    GET_BUFFER_SPACE (1);						\
+    *b++ = (unsigned char) (c);						\
+  } while (0)
+
+
+/* Ensure we have two more bytes of buffer space and then append C1 and C2.  */
+#define BUF_PUSH_2(c1, c2)						\
+  do {									\
+    GET_BUFFER_SPACE (2);						\
+    *b++ = (unsigned char) (c1);					\
+    *b++ = (unsigned char) (c2);					\
+  } while (0)
+
+
+/* As with BUF_PUSH_2, except for three bytes.  */
+#define BUF_PUSH_3(c1, c2, c3)						\
+  do {									\
+    GET_BUFFER_SPACE (3);						\
+    *b++ = (unsigned char) (c1);					\
+    *b++ = (unsigned char) (c2);					\
+    *b++ = (unsigned char) (c3);					\
+  } while (0)
+
+
+/* Store a jump with opcode OP at LOC to location TO.  We store a
+   relative address offset by the three bytes the jump itself occupies.  */
+#define STORE_JUMP(op, loc, to) \
+  store_op1 (op, loc, (to) - (loc) - 3)
+
+/* Likewise, for a two-argument jump.  */
+#define STORE_JUMP2(op, loc, to, arg) \
+  store_op2 (op, loc, (to) - (loc) - 3, arg)
+
+/* Like `STORE_JUMP', but for inserting.  Assume `b' is the buffer end.  */
+#define INSERT_JUMP(op, loc, to) \
+  insert_op1 (op, loc, (to) - (loc) - 3, b)
+
+/* Like `STORE_JUMP2', but for inserting.  Assume `b' is the buffer end.  */
+#define INSERT_JUMP2(op, loc, to, arg) \
+  insert_op2 (op, loc, (to) - (loc) - 3, arg, b)
+
+
+/* This is not an arbitrary limit: the arguments which represent offsets
+   into the pattern are two bytes long.  So if 2^16 bytes turns out to
+   be too small, many things would have to change.  */
+#define MAX_BUF_SIZE (1L << 16)
+
+
+/* Extend the buffer by twice its current size via realloc and
+   reset the pointers that pointed into the old block to point to the
+   correct places in the new one.  If extending the buffer results in it
+   being larger than MAX_BUF_SIZE, then flag memory exhausted.  */
+#define EXTEND_BUFFER()							\
+  do { 									\
+    unsigned char *old_buffer = bufp->buffer;				\
+    if (bufp->allocated == MAX_BUF_SIZE) 				\
+      return REG_ESIZE;							\
+    bufp->allocated <<= 1;						\
+    if (bufp->allocated > MAX_BUF_SIZE)					\
+      bufp->allocated = MAX_BUF_SIZE; 					\
+    bufp->buffer = (unsigned char *) realloc (bufp->buffer, bufp->allocated);\
+    if (bufp->buffer == NULL)						\
+      return REG_ESPACE;						\
+    /* If the buffer moved, move all the pointers into it.  */		\
+    if (old_buffer != bufp->buffer)					\
+      {									\
+        b = (b - old_buffer) + bufp->buffer;				\
+        begalt = (begalt - old_buffer) + bufp->buffer;			\
+        if (fixup_alt_jump)						\
+          fixup_alt_jump = (fixup_alt_jump - old_buffer) + bufp->buffer;\
+        if (laststart)							\
+          laststart = (laststart - old_buffer) + bufp->buffer;		\
+        if (pending_exact)						\
+          pending_exact = (pending_exact - old_buffer) + bufp->buffer;	\
+      }									\
+  } while (0)
+
+
+/* Since we have one byte reserved for the register number argument to
+   {start,stop}_memory, the maximum number of groups we can report
+   things about is what fits in that byte.  */
+#define MAX_REGNUM 255
+
+/* But patterns can have more than `MAX_REGNUM' registers.  We just
+   ignore the excess.  */
+typedef unsigned regnum_t;
+
+
+/* Macros for the compile stack.  */
+
+/* Since offsets can go either forwards or backwards, this type needs to
+   be able to hold values from -(MAX_BUF_SIZE - 1) to MAX_BUF_SIZE - 1.  */
+typedef int pattern_offset_t;
+
+typedef struct
+{
+  pattern_offset_t begalt_offset;
+  pattern_offset_t fixup_alt_jump;
+  pattern_offset_t inner_group_offset;
+  pattern_offset_t laststart_offset;  
+  regnum_t regnum;
+} compile_stack_elt_t;
+
+
+typedef struct
+{
+  compile_stack_elt_t *stack;
+  unsigned size;
+  unsigned avail;			/* Offset of next open position.  */
+} compile_stack_type;
+
+
+#define INIT_COMPILE_STACK_SIZE 32
+
+#define COMPILE_STACK_EMPTY  (compile_stack.avail == 0)
+#define COMPILE_STACK_FULL  (compile_stack.avail == compile_stack.size)
+
+/* The next available element.  */
+#define COMPILE_STACK_TOP (compile_stack.stack[compile_stack.avail])
+
+
+/* Set the bit for character C in a list.  */
+#define SET_LIST_BIT(c)                               \
+  (b[((unsigned char) (c)) / BYTEWIDTH]               \
+   |= 1 << (((unsigned char) c) % BYTEWIDTH))
+
+
+/* Get the next unsigned number in the uncompiled pattern.  */
+#define GET_UNSIGNED_NUMBER(num) 					\
+  { if (p != pend)							\
+     {									\
+       PATFETCH (c); 							\
+       while (ISDIGIT (c)) 						\
+         { 								\
+           if (num < 0)							\
+              num = 0;							\
+           num = num * 10 + c - '0'; 					\
+           if (p == pend) 						\
+              break; 							\
+           PATFETCH (c);						\
+         } 								\
+       } 								\
+    }		
+
+#define CHAR_CLASS_MAX_LENGTH  6 /* Namely, `xdigit'.  */
+
+#define IS_CHAR_CLASS(string)						\
+   (STREQ (string, "alpha") || STREQ (string, "upper")			\
+    || STREQ (string, "lower") || STREQ (string, "digit")		\
+    || STREQ (string, "alnum") || STREQ (string, "xdigit")		\
+    || STREQ (string, "space") || STREQ (string, "print")		\
+    || STREQ (string, "punct") || STREQ (string, "graph")		\
+    || STREQ (string, "cntrl") || STREQ (string, "blank"))
+
+/* `regex_compile' compiles PATTERN (of length SIZE) according to SYNTAX.
+   Returns one of error codes defined in `regex.h', or zero for success.
+
+   Assumes the `allocated' (and perhaps `buffer') and `translate'
+   fields are set in BUFP on entry.
+
+   If it succeeds, results are put in BUFP (if it returns an error, the
+   contents of BUFP are undefined):
+     `buffer' is the compiled pattern;
+     `syntax' is set to SYNTAX;
+     `used' is set to the length of the compiled pattern;
+     `fastmap_accurate' is zero;
+     `re_nsub' is the number of subexpressions in PATTERN;
+     `not_bol' and `not_eol' are zero;
+   
+   The `fastmap' and `newline_anchor' fields are neither
+   examined nor set.  */
+
+/* Return, freeing storage we allocated.  */
+#define FREE_STACK_RETURN(value)		\
+  return (free (compile_stack.stack), value)
+
+static reg_errcode_t
+regex_compile (pattern, size, syntax, bufp)
+     const char *pattern;
+     int size;
+     reg_syntax_t syntax;
+     struct re_pattern_buffer *bufp;
+{
+  /* We fetch characters from PATTERN here.  Even though PATTERN is
+     `char *' (i.e., signed), we declare these variables as unsigned, so
+     they can be reliably used as array indices.  */
+  register unsigned char c, c1;
+  
+  /* A random temporary spot in PATTERN.  */
+  const char *p1;
+
+  /* Points to the end of the buffer, where we should append.  */
+  register unsigned char *b;
+  
+  /* Keeps track of unclosed groups.  */
+  compile_stack_type compile_stack;
+
+  /* Points to the current (ending) position in the pattern.  */
+  const char *p = pattern;
+  const char *pend = pattern + size;
+  
+  /* How to translate the characters in the pattern.  */
+  char *translate = bufp->translate;
+
+  /* Address of the count-byte of the most recently inserted `exactn'
+     command.  This makes it possible to tell if a new exact-match
+     character can be added to that command or if the character requires
+     a new `exactn' command.  */
+  unsigned char *pending_exact = 0;
+
+  /* Address of start of the most recently finished expression.
+     This tells, e.g., postfix * where to find the start of its
+     operand.  Reset at the beginning of groups and alternatives.  */
+  unsigned char *laststart = 0;
+
+  /* Address of beginning of regexp, or inside of last group.  */
+  unsigned char *begalt;
+
+  /* Place in the uncompiled pattern (i.e., the {) to
+     which to go back if the interval is invalid.  */
+  const char *beg_interval;
+                
+  /* Address of the place where a forward jump should go to the end of
+     the containing expression.  Each alternative of an `or' -- except the
+     last -- ends with a forward jump of this sort.  */
+  unsigned char *fixup_alt_jump = 0;
+
+  /* Counts open-groups as they are encountered.  Remembered for the
+     matching close-group on the compile stack, so the same register
+     number is put in the stop_memory as the start_memory.  */
+  regnum_t regnum = 0;
+
+#ifdef DEBUG
+  DEBUG_PRINT1 ("\nCompiling pattern: ");
+  if (debug)
+    {
+      unsigned debug_count;
+      
+      for (debug_count = 0; debug_count < size; debug_count++)
+        printchar (pattern[debug_count]);
+      putchar ('\n');
+    }
+#endif /* DEBUG */
+
+  /* Initialize the compile stack.  */
+  compile_stack.stack = TALLOC (INIT_COMPILE_STACK_SIZE, compile_stack_elt_t);
+  if (compile_stack.stack == NULL)
+    return REG_ESPACE;
+
+  compile_stack.size = INIT_COMPILE_STACK_SIZE;
+  compile_stack.avail = 0;
+
+  /* Initialize the pattern buffer.  */
+  bufp->syntax = syntax;
+  bufp->fastmap_accurate = 0;
+  bufp->not_bol = bufp->not_eol = 0;
+
+  /* Set `used' to zero, so that if we return an error, the pattern
+     printer (for debugging) will think there's no pattern.  We reset it
+     at the end.  */
+  bufp->used = 0;
+  
+  /* Always count groups, whether or not bufp->no_sub is set.  */
+  bufp->re_nsub = 0;				
+
+#if !defined (emacs) && !defined (SYNTAX_TABLE)
+  /* Initialize the syntax table.  */
+   init_syntax_once ();
+#endif
+
+  if (bufp->allocated == 0)
+    {
+      if (bufp->buffer)
+	{ /* If zero allocated, but buffer is non-null, try to realloc
+             enough space.  This loses if buffer's address is bogus, but
+             that is the user's responsibility.  */
+          RETALLOC (bufp->buffer, INIT_BUF_SIZE, unsigned char);
+        }
+      else
+        { /* Caller did not allocate a buffer.  Do it for them.  */
+          bufp->buffer = TALLOC (INIT_BUF_SIZE, unsigned char);
+        }
+      if (!bufp->buffer) FREE_STACK_RETURN (REG_ESPACE);
+
+      bufp->allocated = INIT_BUF_SIZE;
+    }
+
+  begalt = b = bufp->buffer;
+
+  /* Loop through the uncompiled pattern until we're at the end.  */
+  while (p != pend)
+    {
+      PATFETCH (c);
+
+      switch (c)
+        {
+        case '^':
+          {
+            if (   /* If at start of pattern, it's an operator.  */
+                   p == pattern + 1
+                   /* If context independent, it's an operator.  */
+                || syntax & RE_CONTEXT_INDEP_ANCHORS
+                   /* Otherwise, depends on what's come before.  */
+                || at_begline_loc_p (pattern, p, syntax))
+              BUF_PUSH (begline);
+            else
+              goto normal_char;
+          }
+          break;
+
+
+        case '$':
+          {
+            if (   /* If at end of pattern, it's an operator.  */
+                   p == pend 
+                   /* If context independent, it's an operator.  */
+                || syntax & RE_CONTEXT_INDEP_ANCHORS
+                   /* Otherwise, depends on what's next.  */
+                || at_endline_loc_p (p, pend, syntax))
+               BUF_PUSH (endline);
+             else
+               goto normal_char;
+           }
+           break;
+
+
+	case '+':
+        case '?':
+          if ((syntax & RE_BK_PLUS_QM)
+              || (syntax & RE_LIMITED_OPS))
+            goto normal_char;
+        handle_plus:
+        case '*':
+          /* If there is no previous pattern... */
+          if (!laststart)
+            {
+              if (syntax & RE_CONTEXT_INVALID_OPS)
+                FREE_STACK_RETURN (REG_BADRPT);
+              else if (!(syntax & RE_CONTEXT_INDEP_OPS))
+                goto normal_char;
+            }
+
+          {
+            /* Are we optimizing this jump?  */
+            boolean keep_string_p = false;
+            
+            /* 1 means zero (many) matches is allowed.  */
+            char zero_times_ok = 0, many_times_ok = 0;
+
+            /* If there is a sequence of repetition chars, collapse it
+               down to just one (the right one).  We can't combine
+               interval operators with these because of, e.g., `a{2}*',
+               which should only match an even number of `a's.  */
+
+            for (;;)
+              {
+                zero_times_ok |= c != '+';
+                many_times_ok |= c != '?';
+
+                if (p == pend)
+                  break;
+
+                PATFETCH (c);
+
+                if (c == '*'
+                    || (!(syntax & RE_BK_PLUS_QM) && (c == '+' || c == '?')))
+                  ;
+
+                else if (syntax & RE_BK_PLUS_QM  &&  c == '\\')
+                  {
+                    if (p == pend) FREE_STACK_RETURN (REG_EESCAPE);
+
+                    PATFETCH (c1);
+                    if (!(c1 == '+' || c1 == '?'))
+                      {
+                        PATUNFETCH;
+                        PATUNFETCH;
+                        break;
+                      }
+
+                    c = c1;
+                  }
+                else
+                  {
+                    PATUNFETCH;
+                    break;
+                  }
+
+                /* If we get here, we found another repeat character.  */
+               }
+
+            /* Star, etc. applied to an empty pattern is equivalent
+               to an empty pattern.  */
+            if (!laststart)  
+              break;
+
+            /* Now we know whether or not zero matches is allowed
+               and also whether or not two or more matches is allowed.  */
+            if (many_times_ok)
+              { /* More than one repetition is allowed, so put in at the
+                   end a backward relative jump from `b' to before the next
+                   jump we're going to put in below (which jumps from
+                   laststart to after this jump).  
+
+                   But if we are at the `*' in the exact sequence `.*\n',
+                   insert an unconditional jump backwards to the .,
+                   instead of the beginning of the loop.  This way we only
+                   push a failure point once, instead of every time
+                   through the loop.  */
+                assert (p - 1 > pattern);
+
+                /* Allocate the space for the jump.  */
+                GET_BUFFER_SPACE (3);
+
+                /* We know we are not at the first character of the pattern,
+                   because laststart was nonzero.  And we've already
+                   incremented `p', by the way, to be the character after
+                   the `*'.  Do we have to do something analogous here
+                   for null bytes, because of RE_DOT_NOT_NULL?  */
+                if (TRANSLATE (*(p - 2)) == TRANSLATE ('.')
+		    && zero_times_ok
+                    && p < pend && TRANSLATE (*p) == TRANSLATE ('\n')
+                    && !(syntax & RE_DOT_NEWLINE))
+                  { /* We have .*\n.  */
+                    STORE_JUMP (jump, b, laststart);
+                    keep_string_p = true;
+                  }
+                else
+                  /* Anything else.  */
+                  STORE_JUMP (maybe_pop_jump, b, laststart - 3);
+
+                /* We've added more stuff to the buffer.  */
+                b += 3;
+              }
+
+            /* On failure, jump from laststart to b + 3, which will be the
+               end of the buffer after this jump is inserted.  */
+            GET_BUFFER_SPACE (3);
+            INSERT_JUMP (keep_string_p ? on_failure_keep_string_jump
+                                       : on_failure_jump,
+                         laststart, b + 3);
+            pending_exact = 0;
+            b += 3;
+
+            if (!zero_times_ok)
+              {
+                /* At least one repetition is required, so insert a
+                   `dummy_failure_jump' before the initial
+                   `on_failure_jump' instruction of the loop. This
+                   effects a skip over that instruction the first time
+                   we hit that loop.  */
+                GET_BUFFER_SPACE (3);
+                INSERT_JUMP (dummy_failure_jump, laststart, laststart + 6);
+                b += 3;
+              }
+            }
+	  break;
+
+
+	case '.':
+          laststart = b;
+          BUF_PUSH (anychar);
+          break;
+
+
+        case '[':
+          {
+            boolean had_char_class = false;
+
+            if (p == pend) FREE_STACK_RETURN (REG_EBRACK);
+
+            /* Ensure that we have enough space to push a charset: the
+               opcode, the length count, and the bitset; 34 bytes in all.  */
+	    GET_BUFFER_SPACE (34);
+
+            laststart = b;
+
+            /* We test `*p == '^' twice, instead of using an if
+               statement, so we only need one BUF_PUSH.  */
+            BUF_PUSH (*p == '^' ? charset_not : charset); 
+            if (*p == '^')
+              p++;
+
+            /* Remember the first position in the bracket expression.  */
+            p1 = p;
+
+            /* Push the number of bytes in the bitmap.  */
+            BUF_PUSH ((1 << BYTEWIDTH) / BYTEWIDTH);
+
+            /* Clear the whole map.  */
+            bzero (b, (1 << BYTEWIDTH) / BYTEWIDTH);
+
+            /* charset_not matches newline according to a syntax bit.  */
+            if ((re_opcode_t) b[-2] == charset_not
+                && (syntax & RE_HAT_LISTS_NOT_NEWLINE))
+              SET_LIST_BIT ('\n');
+
+            /* Read in characters and ranges, setting map bits.  */
+            for (;;)
+              {
+                if (p == pend) FREE_STACK_RETURN (REG_EBRACK);
+
+                PATFETCH (c);
+
+                /* \ might escape characters inside [...] and [^...].  */
+                if ((syntax & RE_BACKSLASH_ESCAPE_IN_LISTS) && c == '\\')
+                  {
+                    if (p == pend) FREE_STACK_RETURN (REG_EESCAPE);
+
+                    PATFETCH (c1);
+                    SET_LIST_BIT (c1);
+                    continue;
+                  }
+
+                /* Could be the end of the bracket expression.  If it's
+                   not (i.e., when the bracket expression is `[]' so
+                   far), the ']' character bit gets set way below.  */
+                if (c == ']' && p != p1 + 1)
+                  break;
+
+                /* Look ahead to see if it's a range when the last thing
+                   was a character class.  */
+                if (had_char_class && c == '-' && *p != ']')
+                  FREE_STACK_RETURN (REG_ERANGE);
+
+                /* Look ahead to see if it's a range when the last thing
+                   was a character: if this is a hyphen not at the
+                   beginning or the end of a list, then it's the range
+                   operator.  */
+                if (c == '-' 
+                    && !(p - 2 >= pattern && p[-2] == '[') 
+                    && !(p - 3 >= pattern && p[-3] == '[' && p[-2] == '^')
+                    && *p != ']')
+                  {
+                    reg_errcode_t ret
+                      = compile_range (&p, pend, translate, syntax, b);
+                    if (ret != REG_NOERROR) FREE_STACK_RETURN (ret);
+                  }
+
+                else if (p[0] == '-' && p[1] != ']')
+                  { /* This handles ranges made up of characters only.  */
+                    reg_errcode_t ret;
+
+		    /* Move past the `-'.  */
+                    PATFETCH (c1);
+                    
+                    ret = compile_range (&p, pend, translate, syntax, b);
+                    if (ret != REG_NOERROR) FREE_STACK_RETURN (ret);
+                  }
+
+                /* See if we're at the beginning of a possible character
+                   class.  */
+
+                else if (syntax & RE_CHAR_CLASSES && c == '[' && *p == ':')
+                  { /* Leave room for the null.  */
+                    char str[CHAR_CLASS_MAX_LENGTH + 1];
+
+                    PATFETCH (c);
+                    c1 = 0;
+
+                    /* If pattern is `[[:'.  */
+                    if (p == pend) FREE_STACK_RETURN (REG_EBRACK);
+
+                    for (;;)
+                      {
+                        PATFETCH (c);
+                        if (c == ':' || c == ']' || p == pend
+                            || c1 == CHAR_CLASS_MAX_LENGTH)
+                          break;
+                        str[c1++] = c;
+                      }
+                    str[c1] = '\0';
+
+                    /* If isn't a word bracketed by `[:' and:`]':
+                       undo the ending character, the letters, and leave 
+                       the leading `:' and `[' (but set bits for them).  */
+                    if (c == ':' && *p == ']')
+                      {
+                        int ch;
+                        boolean is_alnum = STREQ (str, "alnum");
+                        boolean is_alpha = STREQ (str, "alpha");
+                        boolean is_blank = STREQ (str, "blank");
+                        boolean is_cntrl = STREQ (str, "cntrl");
+                        boolean is_digit = STREQ (str, "digit");
+                        boolean is_graph = STREQ (str, "graph");
+                        boolean is_lower = STREQ (str, "lower");
+                        boolean is_print = STREQ (str, "print");
+                        boolean is_punct = STREQ (str, "punct");
+                        boolean is_space = STREQ (str, "space");
+                        boolean is_upper = STREQ (str, "upper");
+                        boolean is_xdigit = STREQ (str, "xdigit");
+                        
+                        if (!IS_CHAR_CLASS (str))
+			  FREE_STACK_RETURN (REG_ECTYPE);
+
+                        /* Throw away the ] at the end of the character
+                           class.  */
+                        PATFETCH (c);					
+
+                        if (p == pend) FREE_STACK_RETURN (REG_EBRACK);
+
+                        for (ch = 0; ch < 1 << BYTEWIDTH; ch++)
+                          {
+			    /* This was split into 3 if's to
+			       avoid an arbitrary limit in some compiler.  */
+                            if (   (is_alnum  && ISALNUM (ch))
+                                || (is_alpha  && ISALPHA (ch))
+                                || (is_blank  && ISBLANK (ch))
+                                || (is_cntrl  && ISCNTRL (ch)))
+			      SET_LIST_BIT (ch);
+			    if (   (is_digit  && ISDIGIT (ch))
+                                || (is_graph  && ISGRAPH (ch))
+                                || (is_lower  && ISLOWER (ch))
+                                || (is_print  && ISPRINT (ch)))
+			      SET_LIST_BIT (ch);
+			    if (   (is_punct  && ISPUNCT (ch))
+                                || (is_space  && ISSPACE (ch))
+                                || (is_upper  && ISUPPER (ch))
+                                || (is_xdigit && ISXDIGIT (ch)))
+			      SET_LIST_BIT (ch);
+                          }
+                        had_char_class = true;
+                      }
+                    else
+                      {
+                        c1++;
+                        while (c1--)    
+                          PATUNFETCH;
+                        SET_LIST_BIT ('[');
+                        SET_LIST_BIT (':');
+                        had_char_class = false;
+                      }
+                  }
+                else
+                  {
+                    had_char_class = false;
+                    SET_LIST_BIT (c);
+                  }
+              }
+
+            /* Discard any (non)matching list bytes that are all 0 at the
+               end of the map.  Decrease the map-length byte too.  */
+            while ((int) b[-1] > 0 && b[b[-1] - 1] == 0) 
+              b[-1]--; 
+            b += b[-1];
+          }
+          break;
+
+
+	case '(':
+          if (syntax & RE_NO_BK_PARENS)
+            goto handle_open;
+          else
+            goto normal_char;
+
+
+        case ')':
+          if (syntax & RE_NO_BK_PARENS)
+            goto handle_close;
+          else
+            goto normal_char;
+
+
+        case '\n':
+          if (syntax & RE_NEWLINE_ALT)
+            goto handle_alt;
+          else
+            goto normal_char;
+
+
+	case '|':
+          if (syntax & RE_NO_BK_VBAR)
+            goto handle_alt;
+          else
+            goto normal_char;
+
+
+        case '{':
+           if (syntax & RE_INTERVALS && syntax & RE_NO_BK_BRACES)
+             goto handle_interval;
+           else
+             goto normal_char;
+
+
+        case '\\':
+          if (p == pend) FREE_STACK_RETURN (REG_EESCAPE);
+
+          /* Do not translate the character after the \, so that we can
+             distinguish, e.g., \B from \b, even if we normally would
+             translate, e.g., B to b.  */
+          PATFETCH_RAW (c);
+
+          switch (c)
+            {
+            case '(':
+              if (syntax & RE_NO_BK_PARENS)
+                goto normal_backslash;
+
+            handle_open:
+              bufp->re_nsub++;
+              regnum++;
+
+              if (COMPILE_STACK_FULL)
+                { 
+                  RETALLOC (compile_stack.stack, compile_stack.size << 1,
+                            compile_stack_elt_t);
+                  if (compile_stack.stack == NULL) return REG_ESPACE;
+
+                  compile_stack.size <<= 1;
+                }
+
+              /* These are the values to restore when we hit end of this
+                 group.  They are all relative offsets, so that if the
+                 whole pattern moves because of realloc, they will still
+                 be valid.  */
+              COMPILE_STACK_TOP.begalt_offset = begalt - bufp->buffer;
+              COMPILE_STACK_TOP.fixup_alt_jump 
+                = fixup_alt_jump ? fixup_alt_jump - bufp->buffer + 1 : 0;
+              COMPILE_STACK_TOP.laststart_offset = b - bufp->buffer;
+              COMPILE_STACK_TOP.regnum = regnum;
+
+              /* We will eventually replace the 0 with the number of
+                 groups inner to this one.  But do not push a
+                 start_memory for groups beyond the last one we can
+                 represent in the compiled pattern.  */
+              if (regnum <= MAX_REGNUM)
+                {
+                  COMPILE_STACK_TOP.inner_group_offset = b - bufp->buffer + 2;
+                  BUF_PUSH_3 (start_memory, regnum, 0);
+                }
+                
+              compile_stack.avail++;
+
+              fixup_alt_jump = 0;
+              laststart = 0;
+              begalt = b;
+	      /* If we've reached MAX_REGNUM groups, then this open
+		 won't actually generate any code, so we'll have to
+		 clear pending_exact explicitly.  */
+	      pending_exact = 0;
+              break;
+
+
+            case ')':
+              if (syntax & RE_NO_BK_PARENS) goto normal_backslash;
+
+              if (COMPILE_STACK_EMPTY)
+                if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
+                  goto normal_backslash;
+                else
+                  FREE_STACK_RETURN (REG_ERPAREN);
+
+            handle_close:
+              if (fixup_alt_jump)
+                { /* Push a dummy failure point at the end of the
+                     alternative for a possible future
+                     `pop_failure_jump' to pop.  See comments at
+                     `push_dummy_failure' in `re_match_2'.  */
+                  BUF_PUSH (push_dummy_failure);
+                  
+                  /* We allocated space for this jump when we assigned
+                     to `fixup_alt_jump', in the `handle_alt' case below.  */
+                  STORE_JUMP (jump_past_alt, fixup_alt_jump, b - 1);
+                }
+
+              /* See similar code for backslashed left paren above.  */
+              if (COMPILE_STACK_EMPTY)
+                if (syntax & RE_UNMATCHED_RIGHT_PAREN_ORD)
+                  goto normal_char;
+                else
+                  FREE_STACK_RETURN (REG_ERPAREN);
+
+              /* Since we just checked for an empty stack above, this
+                 ``can't happen''.  */
+              assert (compile_stack.avail != 0);
+              {
+                /* We don't just want to restore into `regnum', because
+                   later groups should continue to be numbered higher,
+                   as in `(ab)c(de)' -- the second group is #2.  */
+                regnum_t this_group_regnum;
+
+                compile_stack.avail--;		
+                begalt = bufp->buffer + COMPILE_STACK_TOP.begalt_offset;
+                fixup_alt_jump
+                  = COMPILE_STACK_TOP.fixup_alt_jump
+                    ? bufp->buffer + COMPILE_STACK_TOP.fixup_alt_jump - 1 
+                    : 0;
+                laststart = bufp->buffer + COMPILE_STACK_TOP.laststart_offset;
+                this_group_regnum = COMPILE_STACK_TOP.regnum;
+		/* If we've reached MAX_REGNUM groups, then this open
+		   won't actually generate any code, so we'll have to
+		   clear pending_exact explicitly.  */
+		pending_exact = 0;
+
+                /* We're at the end of the group, so now we know how many
+                   groups were inside this one.  */
+                if (this_group_regnum <= MAX_REGNUM)
+                  {
+                    unsigned char *inner_group_loc
+                      = bufp->buffer + COMPILE_STACK_TOP.inner_group_offset;
+                    
+                    *inner_group_loc = regnum - this_group_regnum;
+                    BUF_PUSH_3 (stop_memory, this_group_regnum,
+                                regnum - this_group_regnum);
+                  }
+              }
+              break;
+
+
+            case '|':					/* `\|'.  */
+              if (syntax & RE_LIMITED_OPS || syntax & RE_NO_BK_VBAR)
+                goto normal_backslash;
+            handle_alt:
+              if (syntax & RE_LIMITED_OPS)
+                goto normal_char;
+
+              /* Insert before the previous alternative a jump which
+                 jumps to this alternative if the former fails.  */
+              GET_BUFFER_SPACE (3);
+              INSERT_JUMP (on_failure_jump, begalt, b + 6);
+              pending_exact = 0;
+              b += 3;
+
+              /* The alternative before this one has a jump after it
+                 which gets executed if it gets matched.  Adjust that
+                 jump so it will jump to this alternative's analogous
+                 jump (put in below, which in turn will jump to the next
+                 (if any) alternative's such jump, etc.).  The last such
+                 jump jumps to the correct final destination.  A picture:
+                          _____ _____ 
+                          |   | |   |   
+                          |   v |   v 
+                         a | b   | c   
+
+                 If we are at `b', then fixup_alt_jump right now points to a
+                 three-byte space after `a'.  We'll put in the jump, set
+                 fixup_alt_jump to right after `b', and leave behind three
+                 bytes which we'll fill in when we get to after `c'.  */
+
+              if (fixup_alt_jump)
+                STORE_JUMP (jump_past_alt, fixup_alt_jump, b);
+
+              /* Mark and leave space for a jump after this alternative,
+                 to be filled in later either by next alternative or
+                 when know we're at the end of a series of alternatives.  */
+              fixup_alt_jump = b;
+              GET_BUFFER_SPACE (3);
+              b += 3;
+
+              laststart = 0;
+              begalt = b;
+              break;
+
+
+            case '{': 
+              /* If \{ is a literal.  */
+              if (!(syntax & RE_INTERVALS)
+                     /* If we're at `\{' and it's not the open-interval 
+                        operator.  */
+                  || ((syntax & RE_INTERVALS) && (syntax & RE_NO_BK_BRACES))
+                  || (p - 2 == pattern  &&  p == pend))
+                goto normal_backslash;
+
+            handle_interval:
+              {
+                /* If got here, then the syntax allows intervals.  */
+
+                /* At least (most) this many matches must be made.  */
+                int lower_bound = -1, upper_bound = -1;
+
+                beg_interval = p - 1;
+
+                if (p == pend)
+                  {
+                    if (syntax & RE_NO_BK_BRACES)
+                      goto unfetch_interval;
+                    else
+                      FREE_STACK_RETURN (REG_EBRACE);
+                  }
+
+                GET_UNSIGNED_NUMBER (lower_bound);
+
+                if (c == ',')
+                  {
+                    GET_UNSIGNED_NUMBER (upper_bound);
+                    if (upper_bound < 0) upper_bound = RE_DUP_MAX;
+                  }
+                else
+                  /* Interval such as `{1}' => match exactly once. */
+                  upper_bound = lower_bound;
+
+                if (lower_bound < 0 || upper_bound > RE_DUP_MAX
+                    || lower_bound > upper_bound)
+                  {
+                    if (syntax & RE_NO_BK_BRACES)
+                      goto unfetch_interval;
+                    else 
+                      FREE_STACK_RETURN (REG_BADBR);
+                  }
+
+                if (!(syntax & RE_NO_BK_BRACES)) 
+                  {
+                    if (c != '\\') FREE_STACK_RETURN (REG_EBRACE);
+
+                    PATFETCH (c);
+                  }
+
+                if (c != '}')
+                  {
+                    if (syntax & RE_NO_BK_BRACES)
+                      goto unfetch_interval;
+                    else 
+                      FREE_STACK_RETURN (REG_BADBR);
+                  }
+
+                /* We just parsed a valid interval.  */
+
+                /* If it's invalid to have no preceding re.  */
+                if (!laststart)
+                  {
+                    if (syntax & RE_CONTEXT_INVALID_OPS)
+                      FREE_STACK_RETURN (REG_BADRPT);
+                    else if (syntax & RE_CONTEXT_INDEP_OPS)
+                      laststart = b;
+                    else
+                      goto unfetch_interval;
+                  }
+
+                /* If the upper bound is zero, don't want to succeed at
+                   all; jump from `laststart' to `b + 3', which will be
+                   the end of the buffer after we insert the jump.  */
+                 if (upper_bound == 0)
+                   {
+                     GET_BUFFER_SPACE (3);
+                     INSERT_JUMP (jump, laststart, b + 3);
+                     b += 3;
+                   }
+
+                 /* Otherwise, we have a nontrivial interval.  When
+                    we're all done, the pattern will look like:
+                      set_number_at <jump count> <upper bound>
+                      set_number_at <succeed_n count> <lower bound>
+                      succeed_n <after jump addr> <succeed_n count>
+                      <body of loop>
+                      jump_n <succeed_n addr> <jump count>
+                    (The upper bound and `jump_n' are omitted if
+                    `upper_bound' is 1, though.)  */
+                 else 
+                   { /* If the upper bound is > 1, we need to insert
+                        more at the end of the loop.  */
+                     unsigned nbytes = 10 + (upper_bound > 1) * 10;
+
+                     GET_BUFFER_SPACE (nbytes);
+
+                     /* Initialize lower bound of the `succeed_n', even
+                        though it will be set during matching by its
+                        attendant `set_number_at' (inserted next),
+                        because `re_compile_fastmap' needs to know.
+                        Jump to the `jump_n' we might insert below.  */
+                     INSERT_JUMP2 (succeed_n, laststart,
+                                   b + 5 + (upper_bound > 1) * 5,
+                                   lower_bound);
+                     b += 5;
+
+                     /* Code to initialize the lower bound.  Insert 
+                        before the `succeed_n'.  The `5' is the last two
+                        bytes of this `set_number_at', plus 3 bytes of
+                        the following `succeed_n'.  */
+                     insert_op2 (set_number_at, laststart, 5, lower_bound, b);
+                     b += 5;
+
+                     if (upper_bound > 1)
+                       { /* More than one repetition is allowed, so
+                            append a backward jump to the `succeed_n'
+                            that starts this interval.
+                            
+                            When we've reached this during matching,
+                            we'll have matched the interval once, so
+                            jump back only `upper_bound - 1' times.  */
+                         STORE_JUMP2 (jump_n, b, laststart + 5,
+                                      upper_bound - 1);
+                         b += 5;
+
+                         /* The location we want to set is the second
+                            parameter of the `jump_n'; that is `b-2' as
+                            an absolute address.  `laststart' will be
+                            the `set_number_at' we're about to insert;
+                            `laststart+3' the number to set, the source
+                            for the relative address.  But we are
+                            inserting into the middle of the pattern --
+                            so everything is getting moved up by 5.
+                            Conclusion: (b - 2) - (laststart + 3) + 5,
+                            i.e., b - laststart.
+                            
+                            We insert this at the beginning of the loop
+                            so that if we fail during matching, we'll
+                            reinitialize the bounds.  */
+                         insert_op2 (set_number_at, laststart, b - laststart,
+                                     upper_bound - 1, b);
+                         b += 5;
+                       }
+                   }
+                pending_exact = 0;
+                beg_interval = NULL;
+              }
+              break;
+
+            unfetch_interval:
+              /* If an invalid interval, match the characters as literals.  */
+               assert (beg_interval);
+               p = beg_interval;
+               beg_interval = NULL;
+
+               /* normal_char and normal_backslash need `c'.  */
+               PATFETCH (c);	
+
+               if (!(syntax & RE_NO_BK_BRACES))
+                 {
+                   if (p > pattern  &&  p[-1] == '\\')
+                     goto normal_backslash;
+                 }
+               goto normal_char;
+
+#ifdef emacs
+            /* There is no way to specify the before_dot and after_dot
+               operators.  rms says this is ok.  --karl  */
+            case '=':
+              BUF_PUSH (at_dot);
+              break;
+
+            case 's':	
+              laststart = b;
+              PATFETCH (c);
+              BUF_PUSH_2 (syntaxspec, syntax_spec_code[c]);
+              break;
+
+            case 'S':
+              laststart = b;
+              PATFETCH (c);
+              BUF_PUSH_2 (notsyntaxspec, syntax_spec_code[c]);
+              break;
+#endif /* emacs */
+
+
+            case 'w':
+              laststart = b;
+              BUF_PUSH (wordchar);
+              break;
+
+
+            case 'W':
+              laststart = b;
+              BUF_PUSH (notwordchar);
+              break;
+
+
+            case '<':
+              BUF_PUSH (wordbeg);
+              break;
+
+            case '>':
+              BUF_PUSH (wordend);
+              break;
+
+            case 'b':
+              BUF_PUSH (wordbound);
+              break;
+
+            case 'B':
+              BUF_PUSH (notwordbound);
+              break;
+
+            case '`':
+              BUF_PUSH (begbuf);
+              break;
+
+            case '\'':
+              BUF_PUSH (endbuf);
+              break;
+
+            case '1': case '2': case '3': case '4': case '5':
+            case '6': case '7': case '8': case '9':
+              if (syntax & RE_NO_BK_REFS)
+                goto normal_char;
+
+              c1 = c - '0';
+
+              if (c1 > regnum)
+                FREE_STACK_RETURN (REG_ESUBREG);
+
+              /* Can't back reference to a subexpression if inside of it.  */
+              if (group_in_compile_stack (compile_stack, c1))
+                goto normal_char;
+
+              laststart = b;
+              BUF_PUSH_2 (duplicate, c1);
+              break;
+
+
+            case '+':
+            case '?':
+              if (syntax & RE_BK_PLUS_QM)
+                goto handle_plus;
+              else
+                goto normal_backslash;
+
+            default:
+            normal_backslash:
+              /* You might think it would be useful for \ to mean
+                 not to translate; but if we don't translate it
+                 it will never match anything.  */
+              c = TRANSLATE (c);
+              goto normal_char;
+            }
+          break;
+
+
+	default:
+        /* Expects the character in `c'.  */
+	normal_char:
+	      /* If no exactn currently being built.  */
+          if (!pending_exact 
+
+              /* If last exactn not at current position.  */
+              || pending_exact + *pending_exact + 1 != b
+              
+              /* We have only one byte following the exactn for the count.  */
+	      || *pending_exact == (1 << BYTEWIDTH) - 1
+
+              /* If followed by a repetition operator.  */
+              || *p == '*' || *p == '^'
+	      || ((syntax & RE_BK_PLUS_QM)
+		  ? *p == '\\' && (p[1] == '+' || p[1] == '?')
+		  : (*p == '+' || *p == '?'))
+	      || ((syntax & RE_INTERVALS)
+                  && ((syntax & RE_NO_BK_BRACES)
+		      ? *p == '{'
+                      : (p[0] == '\\' && p[1] == '{'))))
+	    {
+	      /* Start building a new exactn.  */
+              
+              laststart = b;
+
+	      BUF_PUSH_2 (exactn, 0);
+	      pending_exact = b - 1;
+            }
+            
+	  BUF_PUSH (c);
+          (*pending_exact)++;
+	  break;
+        } /* switch (c) */
+    } /* while p != pend */
+
+  
+  /* Through the pattern now.  */
+  
+  if (fixup_alt_jump)
+    STORE_JUMP (jump_past_alt, fixup_alt_jump, b);
+
+  if (!COMPILE_STACK_EMPTY) 
+    FREE_STACK_RETURN (REG_EPAREN);
+
+  free (compile_stack.stack);
+
+  /* We have succeeded; set the length of the buffer.  */
+  bufp->used = b - bufp->buffer;
+
+#ifdef DEBUG
+  if (debug)
+    {
+      DEBUG_PRINT1 ("\nCompiled pattern: \n");
+      print_compiled_pattern (bufp);
+    }
+#endif /* DEBUG */
+
+#ifndef MATCH_MAY_ALLOCATE
+  /* Initialize the failure stack to the largest possible stack.  This
+     isn't necessary unless we're trying to avoid calling alloca in
+     the search and match routines.  */
+  {
+    int num_regs = bufp->re_nsub + 1;
+
+    /* Since DOUBLE_FAIL_STACK refuses to double only if the current size
+       is strictly greater than re_max_failures, the largest possible stack
+       is 2 * re_max_failures failure points.  */
+    if (fail_stack.size < (2 * re_max_failures * MAX_FAILURE_ITEMS))
+      {
+	fail_stack.size = (2 * re_max_failures * MAX_FAILURE_ITEMS);
+
+#ifdef emacs
+	if (! fail_stack.stack)
+	  fail_stack.stack
+	    = (fail_stack_elt_t *) xmalloc (fail_stack.size 
+					    * sizeof (fail_stack_elt_t));
+	else
+	  fail_stack.stack
+	    = (fail_stack_elt_t *) xrealloc (fail_stack.stack,
+					     (fail_stack.size
+					      * sizeof (fail_stack_elt_t)));
+#else /* not emacs */
+	if (! fail_stack.stack)
+	  fail_stack.stack
+	    = (fail_stack_elt_t *) malloc (fail_stack.size 
+					   * sizeof (fail_stack_elt_t));
+	else
+	  fail_stack.stack
+	    = (fail_stack_elt_t *) realloc (fail_stack.stack,
+					    (fail_stack.size
+					     * sizeof (fail_stack_elt_t)));
+#endif /* not emacs */
+      }
+
+    /* Initialize some other variables the matcher uses.  */
+    RETALLOC_IF (regstart,	 num_regs, const char *);
+    RETALLOC_IF (regend,	 num_regs, const char *);
+    RETALLOC_IF (old_regstart,	 num_regs, const char *);
+    RETALLOC_IF (old_regend,	 num_regs, const char *);
+    RETALLOC_IF (best_regstart,  num_regs, const char *);
+    RETALLOC_IF (best_regend,	 num_regs, const char *);
+    RETALLOC_IF (reg_info,	 num_regs, register_info_type);
+    RETALLOC_IF (reg_dummy,	 num_regs, const char *);
+    RETALLOC_IF (reg_info_dummy, num_regs, register_info_type);
+  }
+#endif
+
+  return REG_NOERROR;
+} /* regex_compile */
+
+/* Subroutines for `regex_compile'.  */
+
+/* Store OP at LOC followed by two-byte integer parameter ARG.  */
+
+static void
+store_op1 (op, loc, arg)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg;
+{
+  *loc = (unsigned char) op;
+  STORE_NUMBER (loc + 1, arg);
+}
+
+
+/* Like `store_op1', but for two two-byte parameters ARG1 and ARG2.  */
+
+static void
+store_op2 (op, loc, arg1, arg2)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg1, arg2;
+{
+  *loc = (unsigned char) op;
+  STORE_NUMBER (loc + 1, arg1);
+  STORE_NUMBER (loc + 3, arg2);
+}
+
+
+/* Copy the bytes from LOC to END to open up three bytes of space at LOC
+   for OP followed by two-byte integer parameter ARG.  */
+
+static void
+insert_op1 (op, loc, arg, end)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg;
+    unsigned char *end;    
+{
+  register unsigned char *pfrom = end;
+  register unsigned char *pto = end + 3;
+
+  while (pfrom != loc)
+    *--pto = *--pfrom;
+    
+  store_op1 (op, loc, arg);
+}
+
+
+/* Like `insert_op1', but for two two-byte parameters ARG1 and ARG2.  */
+
+static void
+insert_op2 (op, loc, arg1, arg2, end)
+    re_opcode_t op;
+    unsigned char *loc;
+    int arg1, arg2;
+    unsigned char *end;    
+{
+  register unsigned char *pfrom = end;
+  register unsigned char *pto = end + 5;
+
+  while (pfrom != loc)
+    *--pto = *--pfrom;
+    
+  store_op2 (op, loc, arg1, arg2);
+}
+
+
+/* P points to just after a ^ in PATTERN.  Return true if that ^ comes
+   after an alternative or a begin-subexpression.  We assume there is at
+   least one character before the ^.  */
+
+static boolean
+at_begline_loc_p (pattern, p, syntax)
+    const char *pattern, *p;
+    reg_syntax_t syntax;
+{
+  const char *prev = p - 2;
+  boolean prev_prev_backslash = prev > pattern && prev[-1] == '\\';
+  
+  return
+       /* After a subexpression?  */
+       (*prev == '(' && (syntax & RE_NO_BK_PARENS || prev_prev_backslash))
+       /* After an alternative?  */
+    || (*prev == '|' && (syntax & RE_NO_BK_VBAR || prev_prev_backslash));
+}
+
+
+/* The dual of at_begline_loc_p.  This one is for $.  We assume there is
+   at least one character after the $, i.e., `P < PEND'.  */
+
+static boolean
+at_endline_loc_p (p, pend, syntax)
+    const char *p, *pend;
+    int syntax;
+{
+  const char *next = p;
+  boolean next_backslash = *next == '\\';
+  const char *next_next = p + 1 < pend ? p + 1 : NULL;
+  
+  return
+       /* Before a subexpression?  */
+       (syntax & RE_NO_BK_PARENS ? *next == ')'
+        : next_backslash && next_next && *next_next == ')')
+       /* Before an alternative?  */
+    || (syntax & RE_NO_BK_VBAR ? *next == '|'
+        : next_backslash && next_next && *next_next == '|');
+}
+
+
+/* Returns true if REGNUM is in one of COMPILE_STACK's elements and 
+   false if it's not.  */
+
+static boolean
+group_in_compile_stack (compile_stack, regnum)
+    compile_stack_type compile_stack;
+    regnum_t regnum;
+{
+  int this_element;
+
+  for (this_element = compile_stack.avail - 1;  
+       this_element >= 0; 
+       this_element--)
+    if (compile_stack.stack[this_element].regnum == regnum)
+      return true;
+
+  return false;
+}
+
+
+/* Read the ending character of a range (in a bracket expression) from the
+   uncompiled pattern *P_PTR (which ends at PEND).  We assume the
+   starting character is in `P[-2]'.  (`P[-1]' is the character `-'.)
+   Then we set the translation of all bits between the starting and
+   ending characters (inclusive) in the compiled pattern B.
+   
+   Return an error code.
+   
+   We use these short variable names so we can use the same macros as
+   `regex_compile' itself.  */
+
+static reg_errcode_t
+compile_range (p_ptr, pend, translate, syntax, b)
+    const char **p_ptr, *pend;
+    char *translate;
+    reg_syntax_t syntax;
+    unsigned char *b;
+{
+  unsigned this_char;
+
+  const char *p = *p_ptr;
+  int range_start, range_end;
+  
+  if (p == pend)
+    return REG_ERANGE;
+
+  /* Even though the pattern is a signed `char *', we need to fetch
+     with unsigned char *'s; if the high bit of the pattern character
+     is set, the range endpoints will be negative if we fetch using a
+     signed char *.
+
+     We also want to fetch the endpoints without translating them; the 
+     appropriate translation is done in the bit-setting loop below.  */
+  /* The SVR4 compiler on the 3B2 had trouble with unsigned const char *.  */
+  range_start = ((const unsigned char *) p)[-2];
+  range_end   = ((const unsigned char *) p)[0];
+
+  /* Have to increment the pointer into the pattern string, so the
+     caller isn't still at the ending character.  */
+  (*p_ptr)++;
+
+  /* If the start is after the end, the range is empty.  */
+  if (range_start > range_end)
+    return syntax & RE_NO_EMPTY_RANGES ? REG_ERANGE : REG_NOERROR;
+
+  /* Here we see why `this_char' has to be larger than an `unsigned
+     char' -- the range is inclusive, so if `range_end' == 0xff
+     (assuming 8-bit characters), we would otherwise go into an infinite
+     loop, since all characters <= 0xff.  */
+  for (this_char = range_start; this_char <= range_end; this_char++)
+    {
+      SET_LIST_BIT (TRANSLATE (this_char));
+    }
+  
+  return REG_NOERROR;
+}
+
+/* re_compile_fastmap computes a ``fastmap'' for the compiled pattern in
+   BUFP.  A fastmap records which of the (1 << BYTEWIDTH) possible
+   characters can start a string that matches the pattern.  This fastmap
+   is used by re_search to skip quickly over impossible starting points.
+
+   The caller must supply the address of a (1 << BYTEWIDTH)-byte data
+   area as BUFP->fastmap.
+   
+   We set the `fastmap', `fastmap_accurate', and `can_be_null' fields in
+   the pattern buffer.
+
+   Returns 0 if we succeed, -2 if an internal error.   */
+
+int
+re_compile_fastmap (bufp)
+     struct re_pattern_buffer *bufp;
+{
+  int j, k;
+#ifdef MATCH_MAY_ALLOCATE
+  fail_stack_type fail_stack;
+#endif
+#ifndef REGEX_MALLOC
+  char *destination;
+#endif
+  /* We don't push any register information onto the failure stack.  */
+  unsigned num_regs = 0;
+  
+  register char *fastmap = bufp->fastmap;
+  unsigned char *pattern = bufp->buffer;
+  unsigned long size = bufp->used;
+  unsigned char *p = pattern;
+  register unsigned char *pend = pattern + size;
+
+  /* Assume that each path through the pattern can be null until
+     proven otherwise.  We set this false at the bottom of switch
+     statement, to which we get only if a particular path doesn't
+     match the empty string.  */
+  boolean path_can_be_null = true;
+
+  /* We aren't doing a `succeed_n' to begin with.  */
+  boolean succeed_n_p = false;
+
+  assert (fastmap != NULL && p != NULL);
+  
+  INIT_FAIL_STACK ();
+  bzero (fastmap, 1 << BYTEWIDTH);  /* Assume nothing's valid.  */
+  bufp->fastmap_accurate = 1;	    /* It will be when we're done.  */
+  bufp->can_be_null = 0;
+      
+  while (p != pend || !FAIL_STACK_EMPTY ())
+    {
+      if (p == pend)
+        {
+          bufp->can_be_null |= path_can_be_null;
+          
+          /* Reset for next path.  */
+          path_can_be_null = true;
+          
+          p = fail_stack.stack[--fail_stack.avail];
+	}
+
+      /* We should never be about to go beyond the end of the pattern.  */
+      assert (p < pend);
+      
+#ifdef SWITCH_ENUM_BUG
+      switch ((int) ((re_opcode_t) *p++))
+#else
+      switch ((re_opcode_t) *p++)
+#endif
+	{
+
+        /* I guess the idea here is to simply not bother with a fastmap
+           if a backreference is used, since it's too hard to figure out
+           the fastmap for the corresponding group.  Setting
+           `can_be_null' stops `re_search_2' from using the fastmap, so
+           that is all we do.  */
+	case duplicate:
+	  bufp->can_be_null = 1;
+          return 0;
+
+
+      /* Following are the cases which match a character.  These end
+         with `break'.  */
+
+	case exactn:
+          fastmap[p[1]] = 1;
+	  break;
+
+
+        case charset:
+          for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
+	    if (p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH)))
+              fastmap[j] = 1;
+	  break;
+
+
+	case charset_not:
+	  /* Chars beyond end of map must be allowed.  */
+	  for (j = *p * BYTEWIDTH; j < (1 << BYTEWIDTH); j++)
+            fastmap[j] = 1;
+
+	  for (j = *p++ * BYTEWIDTH - 1; j >= 0; j--)
+	    if (!(p[j / BYTEWIDTH] & (1 << (j % BYTEWIDTH))))
+              fastmap[j] = 1;
+          break;
+
+
+	case wordchar:
+	  for (j = 0; j < (1 << BYTEWIDTH); j++)
+	    if (SYNTAX (j) == Sword)
+	      fastmap[j] = 1;
+	  break;
+
+
+	case notwordchar:
+	  for (j = 0; j < (1 << BYTEWIDTH); j++)
+	    if (SYNTAX (j) != Sword)
+	      fastmap[j] = 1;
+	  break;
+
+
+        case anychar:
+	  {
+	    int fastmap_newline = fastmap['\n'];
+
+	    /* `.' matches anything ...  */
+	    for (j = 0; j < (1 << BYTEWIDTH); j++)
+	      fastmap[j] = 1;
+
+	    /* ... except perhaps newline.  */
+	    if (!(bufp->syntax & RE_DOT_NEWLINE))
+	      fastmap['\n'] = fastmap_newline;
+
+	    /* Return if we have already set `can_be_null'; if we have,
+	       then the fastmap is irrelevant.  Something's wrong here.  */
+	    else if (bufp->can_be_null)
+	      return 0;
+
+	    /* Otherwise, have to check alternative paths.  */
+	    break;
+	  }
+
+#ifdef emacs
+        case syntaxspec:
+	  k = *p++;
+	  for (j = 0; j < (1 << BYTEWIDTH); j++)
+	    if (SYNTAX (j) == (enum syntaxcode) k)
+	      fastmap[j] = 1;
+	  break;
+
+
+	case notsyntaxspec:
+	  k = *p++;
+	  for (j = 0; j < (1 << BYTEWIDTH); j++)
+	    if (SYNTAX (j) != (enum syntaxcode) k)
+	      fastmap[j] = 1;
+	  break;
+
+
+      /* All cases after this match the empty string.  These end with
+         `continue'.  */
+
+
+	case before_dot:
+	case at_dot:
+	case after_dot:
+          continue;
+#endif /* not emacs */
+
+
+        case no_op:
+        case begline:
+        case endline:
+	case begbuf:
+	case endbuf:
+	case wordbound:
+	case notwordbound:
+	case wordbeg:
+	case wordend:
+        case push_dummy_failure:
+          continue;
+
+
+	case jump_n:
+        case pop_failure_jump:
+	case maybe_pop_jump:
+	case jump:
+        case jump_past_alt:
+	case dummy_failure_jump:
+          EXTRACT_NUMBER_AND_INCR (j, p);
+	  p += j;	
+	  if (j > 0)
+	    continue;
+            
+          /* Jump backward implies we just went through the body of a
+             loop and matched nothing.  Opcode jumped to should be
+             `on_failure_jump' or `succeed_n'.  Just treat it like an
+             ordinary jump.  For a * loop, it has pushed its failure
+             point already; if so, discard that as redundant.  */
+          if ((re_opcode_t) *p != on_failure_jump
+	      && (re_opcode_t) *p != succeed_n)
+	    continue;
+
+          p++;
+          EXTRACT_NUMBER_AND_INCR (j, p);
+          p += j;		
+	  
+          /* If what's on the stack is where we are now, pop it.  */
+          if (!FAIL_STACK_EMPTY () 
+	      && fail_stack.stack[fail_stack.avail - 1] == p)
+            fail_stack.avail--;
+
+          continue;
+
+
+        case on_failure_jump:
+        case on_failure_keep_string_jump:
+	handle_on_failure_jump:
+          EXTRACT_NUMBER_AND_INCR (j, p);
+
+          /* For some patterns, e.g., `(a?)?', `p+j' here points to the
+             end of the pattern.  We don't want to push such a point,
+             since when we restore it above, entering the switch will
+             increment `p' past the end of the pattern.  We don't need
+             to push such a point since we obviously won't find any more
+             fastmap entries beyond `pend'.  Such a pattern can match
+             the null string, though.  */
+          if (p + j < pend)
+            {
+              if (!PUSH_PATTERN_OP (p + j, fail_stack))
+                return -2;
+            }
+          else
+            bufp->can_be_null = 1;
+
+          if (succeed_n_p)
+            {
+              EXTRACT_NUMBER_AND_INCR (k, p);	/* Skip the n.  */
+              succeed_n_p = false;
+	    }
+
+          continue;
+
+
+	case succeed_n:
+          /* Get to the number of times to succeed.  */
+          p += 2;		
+
+          /* Increment p past the n for when k != 0.  */
+          EXTRACT_NUMBER_AND_INCR (k, p);
+          if (k == 0)
+	    {
+              p -= 4;
+  	      succeed_n_p = true;  /* Spaghetti code alert.  */
+              goto handle_on_failure_jump;
+            }
+          continue;
+
+
+	case set_number_at:
+          p += 4;
+          continue;
+
+
+	case start_memory:
+        case stop_memory:
+	  p += 2;
+	  continue;
+
+
+	default:
+          abort (); /* We have listed all the cases.  */
+        } /* switch *p++ */
+
+      /* Getting here means we have found the possible starting
+         characters for one path of the pattern -- and that the empty
+         string does not match.  We need not follow this path further.
+         Instead, look at the next alternative (remembered on the
+         stack), or quit if no more.  The test at the top of the loop
+         does these things.  */
+      path_can_be_null = false;
+      p = pend;
+    } /* while p */
+
+  /* Set `can_be_null' for the last path (also the first path, if the
+     pattern is empty).  */
+  bufp->can_be_null |= path_can_be_null;
+  return 0;
+} /* re_compile_fastmap */
+
+/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
+   ENDS.  Subsequent matches using PATTERN_BUFFER and REGS will use
+   this memory for recording register information.  STARTS and ENDS
+   must be allocated using the malloc library routine, and must each
+   be at least NUM_REGS * sizeof (regoff_t) bytes long.
+
+   If NUM_REGS == 0, then subsequent matches should allocate their own
+   register data.
+
+   Unless this function is called, the first search or match using
+   PATTERN_BUFFER will allocate its own register data, without
+   freeing the old data.  */
+
+void
+re_set_registers (bufp, regs, num_regs, starts, ends)
+    struct re_pattern_buffer *bufp;
+    struct re_registers *regs;
+    unsigned num_regs;
+    regoff_t *starts, *ends;
+{
+  if (num_regs)
+    {
+      bufp->regs_allocated = REGS_REALLOCATE;
+      regs->num_regs = num_regs;
+      regs->start = starts;
+      regs->end = ends;
+    }
+  else
+    {
+      bufp->regs_allocated = REGS_UNALLOCATED;
+      regs->num_regs = 0;
+      regs->start = regs->end = (regoff_t *) 0;
+    }
+}
+
+/* Searching routines.  */
+
+/* Like re_search_2, below, but only one string is specified, and
+   doesn't let you say where to stop matching. */
+
+int
+re_search (bufp, string, size, startpos, range, regs)
+     struct re_pattern_buffer *bufp;
+     const char *string;
+     int size, startpos, range;
+     struct re_registers *regs;
+{
+  return re_search_2 (bufp, NULL, 0, string, size, startpos, range, 
+		      regs, size);
+}
+
+
+/* Using the compiled pattern in BUFP->buffer, first tries to match the
+   virtual concatenation of STRING1 and STRING2, starting first at index
+   STARTPOS, then at STARTPOS + 1, and so on.
+   
+   STRING1 and STRING2 have length SIZE1 and SIZE2, respectively.
+   
+   RANGE is how far to scan while trying to match.  RANGE = 0 means try
+   only at STARTPOS; in general, the last start tried is STARTPOS +
+   RANGE.
+   
+   In REGS, return the indices of the virtual concatenation of STRING1
+   and STRING2 that matched the entire BUFP->buffer and its contained
+   subexpressions.
+   
+   Do not consider matching one past the index STOP in the virtual
+   concatenation of STRING1 and STRING2.
+
+   We return either the position in the strings at which the match was
+   found, -1 if no match, or -2 if error (such as failure
+   stack overflow).  */
+
+int
+re_search_2 (bufp, string1, size1, string2, size2, startpos, range, regs, stop)
+     struct re_pattern_buffer *bufp;
+     const char *string1, *string2;
+     int size1, size2;
+     int startpos;
+     int range;
+     struct re_registers *regs;
+     int stop;
+{
+  int val;
+  register char *fastmap = bufp->fastmap;
+  register char *translate = bufp->translate;
+  int total_size = size1 + size2;
+  int endpos = startpos + range;
+
+  /* Check for out-of-range STARTPOS.  */
+  if (startpos < 0 || startpos > total_size)
+    return -1;
+    
+  /* Fix up RANGE if it might eventually take us outside
+     the virtual concatenation of STRING1 and STRING2.  */
+  if (endpos < -1)
+    range = -1 - startpos;
+  else if (endpos > total_size)
+    range = total_size - startpos;
+
+  /* If the search isn't to be a backwards one, don't waste time in a
+     search for a pattern that must be anchored.  */
+  if (bufp->used > 0 && (re_opcode_t) bufp->buffer[0] == begbuf && range > 0)
+    {
+      if (startpos > 0)
+	return -1;
+      else
+	range = 1;
+    }
+
+  /* Update the fastmap now if not correct already.  */
+  if (fastmap && !bufp->fastmap_accurate)
+    if (re_compile_fastmap (bufp) == -2)
+      return -2;
+  
+  /* Loop through the string, looking for a place to start matching.  */
+  for (;;)
+    { 
+      /* If a fastmap is supplied, skip quickly over characters that
+         cannot be the start of a match.  If the pattern can match the
+         null string, however, we don't need to skip characters; we want
+         the first null string.  */
+      if (fastmap && startpos < total_size && !bufp->can_be_null)
+	{
+	  if (range > 0)	/* Searching forwards.  */
+	    {
+	      register const char *d;
+	      register int lim = 0;
+	      int irange = range;
+
+              if (startpos < size1 && startpos + range >= size1)
+                lim = range - (size1 - startpos);
+
+	      d = (startpos >= size1 ? string2 - size1 : string1) + startpos;
+   
+              /* Written out as an if-else to avoid testing `translate'
+                 inside the loop.  */
+	      if (translate)
+                while (range > lim
+                       && !fastmap[(unsigned char)
+				   translate[(unsigned char) *d++]])
+                  range--;
+	      else
+                while (range > lim && !fastmap[(unsigned char) *d++])
+                  range--;
+
+	      startpos += irange - range;
+	    }
+	  else				/* Searching backwards.  */
+	    {
+	      register char c = (size1 == 0 || startpos >= size1
+                                 ? string2[startpos - size1] 
+                                 : string1[startpos]);
+
+	      if (!fastmap[(unsigned char) TRANSLATE (c)])
+		goto advance;
+	    }
+	}
+
+      /* If can't match the null string, and that's all we have left, fail.  */
+      if (range >= 0 && startpos == total_size && fastmap
+          && !bufp->can_be_null)
+	return -1;
+
+      val = re_match_2_internal (bufp, string1, size1, string2, size2,
+				 startpos, regs, stop);
+#ifndef REGEX_MALLOC
+#ifdef C_ALLOCA
+      alloca (0);
+#endif
+#endif
+
+      if (val >= 0)
+	return startpos;
+        
+      if (val == -2)
+	return -2;
+
+    advance:
+      if (!range) 
+        break;
+      else if (range > 0) 
+        {
+          range--; 
+          startpos++;
+        }
+      else
+        {
+          range++; 
+          startpos--;
+        }
+    }
+  return -1;
+} /* re_search_2 */
+
+/* Declarations and macros for re_match_2.  */
+
+static int bcmp_translate ();
+static boolean alt_match_null_string_p (),
+               common_op_match_null_string_p (),
+               group_match_null_string_p ();
+
+/* This converts PTR, a pointer into one of the search strings `string1'
+   and `string2' into an offset from the beginning of that string.  */
+#define POINTER_TO_OFFSET(ptr)			\
+  (FIRST_STRING_P (ptr)				\
+   ? ((regoff_t) ((ptr) - string1))		\
+   : ((regoff_t) ((ptr) - string2 + size1)))
+
+/* Macros for dealing with the split strings in re_match_2.  */
+
+#define MATCHING_IN_FIRST_STRING  (dend == end_match_1)
+
+/* Call before fetching a character with *d.  This switches over to
+   string2 if necessary.  */
+#define PREFETCH()							\
+  while (d == dend)						    	\
+    {									\
+      /* End of string2 => fail.  */					\
+      if (dend == end_match_2) 						\
+        goto fail;							\
+      /* End of string1 => advance to string2.  */ 			\
+      d = string2;						        \
+      dend = end_match_2;						\
+    }
+
+
+/* Test if at very beginning or at very end of the virtual concatenation
+   of `string1' and `string2'.  If only one string, it's `string2'.  */
+#define AT_STRINGS_BEG(d) ((d) == (size1 ? string1 : string2) || !size2)
+#define AT_STRINGS_END(d) ((d) == end2)	
+
+
+/* Test if D points to a character which is word-constituent.  We have
+   two special cases to check for: if past the end of string1, look at
+   the first character in string2; and if before the beginning of
+   string2, look at the last character in string1.  */
+#define WORDCHAR_P(d)							\
+  (SYNTAX ((d) == end1 ? *string2					\
+           : (d) == string2 - 1 ? *(end1 - 1) : *(d))			\
+   == Sword)
+
+/* Test if the character before D and the one at D differ with respect
+   to being word-constituent.  */
+#define AT_WORD_BOUNDARY(d)						\
+  (AT_STRINGS_BEG (d) || AT_STRINGS_END (d)				\
+   || WORDCHAR_P (d - 1) != WORDCHAR_P (d))
+
+
+/* Free everything we malloc.  */
+#ifdef MATCH_MAY_ALLOCATE
+#ifdef REGEX_MALLOC
+#define FREE_VAR(var) if (var) free (var); var = NULL
+#define FREE_VARIABLES()						\
+  do {									\
+    FREE_VAR (fail_stack.stack);					\
+    FREE_VAR (regstart);						\
+    FREE_VAR (regend);							\
+    FREE_VAR (old_regstart);						\
+    FREE_VAR (old_regend);						\
+    FREE_VAR (best_regstart);						\
+    FREE_VAR (best_regend);						\
+    FREE_VAR (reg_info);						\
+    FREE_VAR (reg_dummy);						\
+    FREE_VAR (reg_info_dummy);						\
+  } while (0)
+#else /* not REGEX_MALLOC */
+/* This used to do alloca (0), but now we do that in the caller.  */
+#define FREE_VARIABLES() /* Nothing */
+#endif /* not REGEX_MALLOC */
+#else
+#define FREE_VARIABLES() /* Do nothing!  */
+#endif /* not MATCH_MAY_ALLOCATE */
+
+/* These values must meet several constraints.  They must not be valid
+   register values; since we have a limit of 255 registers (because
+   we use only one byte in the pattern for the register number), we can
+   use numbers larger than 255.  They must differ by 1, because of
+   NUM_FAILURE_ITEMS above.  And the value for the lowest register must
+   be larger than the value for the highest register, so we do not try
+   to actually save any registers when none are active.  */
+#define NO_HIGHEST_ACTIVE_REG (1 << BYTEWIDTH)
+#define NO_LOWEST_ACTIVE_REG (NO_HIGHEST_ACTIVE_REG + 1)
+
+/* Matching routines.  */
+
+#ifndef emacs   /* Emacs never uses this.  */
+/* re_match is like re_match_2 except it takes only a single string.  */
+
+int
+re_match (bufp, string, size, pos, regs)
+     struct re_pattern_buffer *bufp;
+     const char *string;
+     int size, pos;
+     struct re_registers *regs;
+{
+  int result = re_match_2_internal (bufp, NULL, 0, string, size,
+				    pos, regs, size);
+  alloca (0);
+  return result;
+}
+#endif /* not emacs */
+
+
+/* re_match_2 matches the compiled pattern in BUFP against the
+   the (virtual) concatenation of STRING1 and STRING2 (of length SIZE1
+   and SIZE2, respectively).  We start matching at POS, and stop
+   matching at STOP.
+   
+   If REGS is non-null and the `no_sub' field of BUFP is nonzero, we
+   store offsets for the substring each group matched in REGS.  See the
+   documentation for exactly how many groups we fill.
+
+   We return -1 if no match, -2 if an internal error (such as the
+   failure stack overflowing).  Otherwise, we return the length of the
+   matched substring.  */
+
+int
+re_match_2 (bufp, string1, size1, string2, size2, pos, regs, stop)
+     struct re_pattern_buffer *bufp;
+     const char *string1, *string2;
+     int size1, size2;
+     int pos;
+     struct re_registers *regs;
+     int stop;
+{
+  int result = re_match_2_internal (bufp, string1, size1, string2, size2,
+				    pos, regs, stop);
+  alloca (0);
+  return result;
+}
+
+/* This is a separate function so that we can force an alloca cleanup
+   afterwards.  */
+static int
+re_match_2_internal (bufp, string1, size1, string2, size2, pos, regs, stop)
+     struct re_pattern_buffer *bufp;
+     const char *string1, *string2;
+     int size1, size2;
+     int pos;
+     struct re_registers *regs;
+     int stop;
+{
+  /* General temporaries.  */
+  int mcnt;
+  unsigned char *p1;
+
+  /* Just past the end of the corresponding string.  */
+  const char *end1, *end2;
+
+  /* Pointers into string1 and string2, just past the last characters in
+     each to consider matching.  */
+  const char *end_match_1, *end_match_2;
+
+  /* Where we are in the data, and the end of the current string.  */
+  const char *d, *dend;
+  
+  /* Where we are in the pattern, and the end of the pattern.  */
+  unsigned char *p = bufp->buffer;
+  register unsigned char *pend = p + bufp->used;
+
+  /* Mark the opcode just after a start_memory, so we can test for an
+     empty subpattern when we get to the stop_memory.  */
+  unsigned char *just_past_start_mem = 0;
+
+  /* We use this to map every character in the string.  */
+  char *translate = bufp->translate;
+
+  /* Failure point stack.  Each place that can handle a failure further
+     down the line pushes a failure point on this stack.  It consists of
+     restart, regend, and reg_info for all registers corresponding to
+     the subexpressions we're currently inside, plus the number of such
+     registers, and, finally, two char *'s.  The first char * is where
+     to resume scanning the pattern; the second one is where to resume
+     scanning the strings.  If the latter is zero, the failure point is
+     a ``dummy''; if a failure happens and the failure point is a dummy,
+     it gets discarded and the next next one is tried.  */
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, this is global.  */
+  fail_stack_type fail_stack;
+#endif
+#ifdef DEBUG
+  static unsigned failure_id = 0;
+  unsigned nfailure_points_pushed = 0, nfailure_points_popped = 0;
+#endif
+
+  /* We fill all the registers internally, independent of what we
+     return, for use in backreferences.  The number here includes
+     an element for register zero.  */
+  unsigned num_regs = bufp->re_nsub + 1;
+  
+  /* The currently active registers.  */
+  unsigned lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+  unsigned highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+
+  /* Information on the contents of registers. These are pointers into
+     the input strings; they record just what was matched (on this
+     attempt) by a subexpression part of the pattern, that is, the
+     regnum-th regstart pointer points to where in the pattern we began
+     matching and the regnum-th regend points to right after where we
+     stopped matching the regnum-th subexpression.  (The zeroth register
+     keeps track of what the whole pattern matches.)  */
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, these are global.  */
+  const char **regstart, **regend;
+#endif
+
+  /* If a group that's operated upon by a repetition operator fails to
+     match anything, then the register for its start will need to be
+     restored because it will have been set to wherever in the string we
+     are when we last see its open-group operator.  Similarly for a
+     register's end.  */
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, these are global.  */
+  const char **old_regstart, **old_regend;
+#endif
+
+  /* The is_active field of reg_info helps us keep track of which (possibly
+     nested) subexpressions we are currently in. The matched_something
+     field of reg_info[reg_num] helps us tell whether or not we have
+     matched any of the pattern so far this time through the reg_num-th
+     subexpression.  These two fields get reset each time through any
+     loop their register is in.  */
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, this is global.  */
+  register_info_type *reg_info; 
+#endif
+
+  /* The following record the register info as found in the above
+     variables when we find a match better than any we've seen before. 
+     This happens as we backtrack through the failure points, which in
+     turn happens only if we have not yet matched the entire string. */
+  unsigned best_regs_set = false;
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, these are global.  */
+  const char **best_regstart, **best_regend;
+#endif
+  
+  /* Logically, this is `best_regend[0]'.  But we don't want to have to
+     allocate space for that if we're not allocating space for anything
+     else (see below).  Also, we never need info about register 0 for
+     any of the other register vectors, and it seems rather a kludge to
+     treat `best_regend' differently than the rest.  So we keep track of
+     the end of the best match so far in a separate variable.  We
+     initialize this to NULL so that when we backtrack the first time
+     and need to test it, it's not garbage.  */
+  const char *match_end = NULL;
+
+  /* Used when we pop values we don't care about.  */
+#ifdef MATCH_MAY_ALLOCATE /* otherwise, these are global.  */
+  const char **reg_dummy;
+  register_info_type *reg_info_dummy;
+#endif
+
+#ifdef DEBUG
+  /* Counts the total number of registers pushed.  */
+  unsigned num_regs_pushed = 0; 	
+#endif
+
+  DEBUG_PRINT1 ("\n\nEntering re_match_2.\n");
+  
+  INIT_FAIL_STACK ();
+  
+#ifdef MATCH_MAY_ALLOCATE
+  /* Do not bother to initialize all the register variables if there are
+     no groups in the pattern, as it takes a fair amount of time.  If
+     there are groups, we include space for register 0 (the whole
+     pattern), even though we never use it, since it simplifies the
+     array indexing.  We should fix this.  */
+  if (bufp->re_nsub)
+    {
+      regstart = REGEX_TALLOC (num_regs, const char *);
+      regend = REGEX_TALLOC (num_regs, const char *);
+      old_regstart = REGEX_TALLOC (num_regs, const char *);
+      old_regend = REGEX_TALLOC (num_regs, const char *);
+      best_regstart = REGEX_TALLOC (num_regs, const char *);
+      best_regend = REGEX_TALLOC (num_regs, const char *);
+      reg_info = REGEX_TALLOC (num_regs, register_info_type);
+      reg_dummy = REGEX_TALLOC (num_regs, const char *);
+      reg_info_dummy = REGEX_TALLOC (num_regs, register_info_type);
+
+      if (!(regstart && regend && old_regstart && old_regend && reg_info 
+            && best_regstart && best_regend && reg_dummy && reg_info_dummy)) 
+        {
+          FREE_VARIABLES ();
+          return -2;
+        }
+    }
+#if defined (REGEX_MALLOC)
+  else
+    {
+      /* We must initialize all our variables to NULL, so that
+         `FREE_VARIABLES' doesn't try to free them.  */
+      regstart = regend = old_regstart = old_regend = best_regstart
+        = best_regend = reg_dummy = NULL;
+      reg_info = reg_info_dummy = (register_info_type *) NULL;
+    }
+#endif /* REGEX_MALLOC */
+#endif /* MATCH_MAY_ALLOCATE */
+
+  /* The starting position is bogus.  */
+  if (pos < 0 || pos > size1 + size2)
+    {
+      FREE_VARIABLES ();
+      return -1;
+    }
+    
+  /* Initialize subexpression text positions to -1 to mark ones that no
+     start_memory/stop_memory has been seen for. Also initialize the
+     register information struct.  */
+  for (mcnt = 1; mcnt < num_regs; mcnt++)
+    {
+      regstart[mcnt] = regend[mcnt] 
+        = old_regstart[mcnt] = old_regend[mcnt] = REG_UNSET_VALUE;
+        
+      REG_MATCH_NULL_STRING_P (reg_info[mcnt]) = MATCH_NULL_UNSET_VALUE;
+      IS_ACTIVE (reg_info[mcnt]) = 0;
+      MATCHED_SOMETHING (reg_info[mcnt]) = 0;
+      EVER_MATCHED_SOMETHING (reg_info[mcnt]) = 0;
+    }
+  
+  /* We move `string1' into `string2' if the latter's empty -- but not if
+     `string1' is null.  */
+  if (size2 == 0 && string1 != NULL)
+    {
+      string2 = string1;
+      size2 = size1;
+      string1 = 0;
+      size1 = 0;
+    }
+  end1 = string1 + size1;
+  end2 = string2 + size2;
+
+  /* Compute where to stop matching, within the two strings.  */
+  if (stop <= size1)
+    {
+      end_match_1 = string1 + stop;
+      end_match_2 = string2;
+    }
+  else
+    {
+      end_match_1 = end1;
+      end_match_2 = string2 + stop - size1;
+    }
+
+  /* `p' scans through the pattern as `d' scans through the data. 
+     `dend' is the end of the input string that `d' points within.  `d'
+     is advanced into the following input string whenever necessary, but
+     this happens before fetching; therefore, at the beginning of the
+     loop, `d' can be pointing at the end of a string, but it cannot
+     equal `string2'.  */
+  if (size1 > 0 && pos <= size1)
+    {
+      d = string1 + pos;
+      dend = end_match_1;
+    }
+  else
+    {
+      d = string2 + pos - size1;
+      dend = end_match_2;
+    }
+
+  DEBUG_PRINT1 ("The compiled pattern is: ");
+  DEBUG_PRINT_COMPILED_PATTERN (bufp, p, pend);
+  DEBUG_PRINT1 ("The string to match is: `");
+  DEBUG_PRINT_DOUBLE_STRING (d, string1, size1, string2, size2);
+  DEBUG_PRINT1 ("'\n");
+  
+  /* This loops over pattern commands.  It exits by returning from the
+     function if the match is complete, or it drops through if the match
+     fails at this starting point in the input data.  */
+  for (;;)
+    {
+      DEBUG_PRINT2 ("\n0x%x: ", p);
+
+      if (p == pend)
+	{ /* End of pattern means we might have succeeded.  */
+          DEBUG_PRINT1 ("end of pattern ... ");
+          
+	  /* If we haven't matched the entire string, and we want the
+             longest match, try backtracking.  */
+          if (d != end_match_2)
+	    {
+	      /* 1 if this match ends in the same string (string1 or string2)
+		 as the best previous match.  */
+	      boolean same_str_p = (FIRST_STRING_P (match_end) 
+				    == MATCHING_IN_FIRST_STRING);
+	      /* 1 if this match is the best seen so far.  */
+	      boolean best_match_p;
+
+	      /* AIX compiler got confused when this was combined
+		 with the previous declaration.  */
+	      if (same_str_p)
+		best_match_p = d > match_end;
+	      else
+		best_match_p = !MATCHING_IN_FIRST_STRING;
+
+              DEBUG_PRINT1 ("backtracking.\n");
+              
+              if (!FAIL_STACK_EMPTY ())
+                { /* More failure points to try.  */
+
+                  /* If exceeds best match so far, save it.  */
+                  if (!best_regs_set || best_match_p)
+                    {
+                      best_regs_set = true;
+                      match_end = d;
+                      
+                      DEBUG_PRINT1 ("\nSAVING match as best so far.\n");
+                      
+                      for (mcnt = 1; mcnt < num_regs; mcnt++)
+                        {
+                          best_regstart[mcnt] = regstart[mcnt];
+                          best_regend[mcnt] = regend[mcnt];
+                        }
+                    }
+                  goto fail;	       
+                }
+
+              /* If no failure points, don't restore garbage.  And if
+                 last match is real best match, don't restore second
+                 best one. */
+              else if (best_regs_set && !best_match_p)
+                {
+  	        restore_best_regs:
+                  /* Restore best match.  It may happen that `dend ==
+                     end_match_1' while the restored d is in string2.
+                     For example, the pattern `x.*y.*z' against the
+                     strings `x-' and `y-z-', if the two strings are
+                     not consecutive in memory.  */
+                  DEBUG_PRINT1 ("Restoring best registers.\n");
+                  
+                  d = match_end;
+                  dend = ((d >= string1 && d <= end1)
+		           ? end_match_1 : end_match_2);
+
+		  for (mcnt = 1; mcnt < num_regs; mcnt++)
+		    {
+		      regstart[mcnt] = best_regstart[mcnt];
+		      regend[mcnt] = best_regend[mcnt];
+		    }
+                }
+            } /* d != end_match_2 */
+
+          DEBUG_PRINT1 ("Accepting match.\n");
+
+          /* If caller wants register contents data back, do it.  */
+          if (regs && !bufp->no_sub)
+	    {
+              /* Have the register data arrays been allocated?  */
+              if (bufp->regs_allocated == REGS_UNALLOCATED)
+                { /* No.  So allocate them with malloc.  We need one
+                     extra element beyond `num_regs' for the `-1' marker
+                     GNU code uses.  */
+                  regs->num_regs = MAX (RE_NREGS, num_regs + 1);
+                  regs->start = TALLOC (regs->num_regs, regoff_t);
+                  regs->end = TALLOC (regs->num_regs, regoff_t);
+                  if (regs->start == NULL || regs->end == NULL)
+                    return -2;
+                  bufp->regs_allocated = REGS_REALLOCATE;
+                }
+              else if (bufp->regs_allocated == REGS_REALLOCATE)
+                { /* Yes.  If we need more elements than were already
+                     allocated, reallocate them.  If we need fewer, just
+                     leave it alone.  */
+                  if (regs->num_regs < num_regs + 1)
+                    {
+                      regs->num_regs = num_regs + 1;
+                      RETALLOC (regs->start, regs->num_regs, regoff_t);
+                      RETALLOC (regs->end, regs->num_regs, regoff_t);
+                      if (regs->start == NULL || regs->end == NULL)
+                        return -2;
+                    }
+                }
+              else
+		{
+		  /* These braces fend off a "empty body in an else-statement"
+		     warning under GCC when assert expands to nothing.  */
+		  assert (bufp->regs_allocated == REGS_FIXED);
+		}
+
+              /* Convert the pointer data in `regstart' and `regend' to
+                 indices.  Register zero has to be set differently,
+                 since we haven't kept track of any info for it.  */
+              if (regs->num_regs > 0)
+                {
+                  regs->start[0] = pos;
+                  regs->end[0] = (MATCHING_IN_FIRST_STRING
+				  ? ((regoff_t) (d - string1))
+			          : ((regoff_t) (d - string2 + size1)));
+                }
+              
+              /* Go through the first `min (num_regs, regs->num_regs)'
+                 registers, since that is all we initialized.  */
+	      for (mcnt = 1; mcnt < MIN (num_regs, regs->num_regs); mcnt++)
+		{
+                  if (REG_UNSET (regstart[mcnt]) || REG_UNSET (regend[mcnt]))
+                    regs->start[mcnt] = regs->end[mcnt] = -1;
+                  else
+                    {
+		      regs->start[mcnt]
+			= (regoff_t) POINTER_TO_OFFSET (regstart[mcnt]);
+                      regs->end[mcnt]
+			= (regoff_t) POINTER_TO_OFFSET (regend[mcnt]);
+                    }
+		}
+              
+              /* If the regs structure we return has more elements than
+                 were in the pattern, set the extra elements to -1.  If
+                 we (re)allocated the registers, this is the case,
+                 because we always allocate enough to have at least one
+                 -1 at the end.  */
+              for (mcnt = num_regs; mcnt < regs->num_regs; mcnt++)
+                regs->start[mcnt] = regs->end[mcnt] = -1;
+	    } /* regs && !bufp->no_sub */
+
+          FREE_VARIABLES ();
+          DEBUG_PRINT4 ("%u failure points pushed, %u popped (%u remain).\n",
+                        nfailure_points_pushed, nfailure_points_popped,
+                        nfailure_points_pushed - nfailure_points_popped);
+          DEBUG_PRINT2 ("%u registers pushed.\n", num_regs_pushed);
+
+          mcnt = d - pos - (MATCHING_IN_FIRST_STRING 
+			    ? string1 
+			    : string2 - size1);
+
+          DEBUG_PRINT2 ("Returning %d from re_match_2.\n", mcnt);
+
+          return mcnt;
+        }
+
+      /* Otherwise match next pattern command.  */
+#ifdef SWITCH_ENUM_BUG
+      switch ((int) ((re_opcode_t) *p++))
+#else
+      switch ((re_opcode_t) *p++)
+#endif
+	{
+        /* Ignore these.  Used to ignore the n of succeed_n's which
+           currently have n == 0.  */
+        case no_op:
+          DEBUG_PRINT1 ("EXECUTING no_op.\n");
+          break;
+
+
+        /* Match the next n pattern characters exactly.  The following
+           byte in the pattern defines n, and the n bytes after that
+           are the characters to match.  */
+	case exactn:
+	  mcnt = *p++;
+          DEBUG_PRINT2 ("EXECUTING exactn %d.\n", mcnt);
+
+          /* This is written out as an if-else so we don't waste time
+             testing `translate' inside the loop.  */
+          if (translate)
+	    {
+	      do
+		{
+		  PREFETCH ();
+		  if (translate[(unsigned char) *d++] != (char) *p++)
+                    goto fail;
+		}
+	      while (--mcnt);
+	    }
+	  else
+	    {
+	      do
+		{
+		  PREFETCH ();
+		  if (*d++ != (char) *p++) goto fail;
+		}
+	      while (--mcnt);
+	    }
+	  SET_REGS_MATCHED ();
+          break;
+
+
+        /* Match any character except possibly a newline or a null.  */
+	case anychar:
+          DEBUG_PRINT1 ("EXECUTING anychar.\n");
+
+          PREFETCH ();
+
+          if ((!(bufp->syntax & RE_DOT_NEWLINE) && TRANSLATE (*d) == '\n')
+              || (bufp->syntax & RE_DOT_NOT_NULL && TRANSLATE (*d) == '\000'))
+	    goto fail;
+
+          SET_REGS_MATCHED ();
+          DEBUG_PRINT2 ("  Matched `%d'.\n", *d);
+          d++;
+	  break;
+
+
+	case charset:
+	case charset_not:
+	  {
+	    register unsigned char c;
+	    boolean not = (re_opcode_t) *(p - 1) == charset_not;
+
+            DEBUG_PRINT2 ("EXECUTING charset%s.\n", not ? "_not" : "");
+
+	    PREFETCH ();
+	    c = TRANSLATE (*d); /* The character to match.  */
+
+            /* Cast to `unsigned' instead of `unsigned char' in case the
+               bit list is a full 32 bytes long.  */
+	    if (c < (unsigned) (*p * BYTEWIDTH)
+		&& p[1 + c / BYTEWIDTH] & (1 << (c % BYTEWIDTH)))
+	      not = !not;
+
+	    p += 1 + *p;
+
+	    if (!not) goto fail;
+            
+	    SET_REGS_MATCHED ();
+            d++;
+	    break;
+	  }
+
+
+        /* The beginning of a group is represented by start_memory.
+           The arguments are the register number in the next byte, and the
+           number of groups inner to this one in the next.  The text
+           matched within the group is recorded (in the internal
+           registers data structure) under the register number.  */
+        case start_memory:
+	  DEBUG_PRINT3 ("EXECUTING start_memory %d (%d):\n", *p, p[1]);
+
+          /* Find out if this group can match the empty string.  */
+	  p1 = p;		/* To send to group_match_null_string_p.  */
+          
+          if (REG_MATCH_NULL_STRING_P (reg_info[*p]) == MATCH_NULL_UNSET_VALUE)
+            REG_MATCH_NULL_STRING_P (reg_info[*p]) 
+              = group_match_null_string_p (&p1, pend, reg_info);
+
+          /* Save the position in the string where we were the last time
+             we were at this open-group operator in case the group is
+             operated upon by a repetition operator, e.g., with `(a*)*b'
+             against `ab'; then we want to ignore where we are now in
+             the string in case this attempt to match fails.  */
+          old_regstart[*p] = REG_MATCH_NULL_STRING_P (reg_info[*p])
+                             ? REG_UNSET (regstart[*p]) ? d : regstart[*p]
+                             : regstart[*p];
+	  DEBUG_PRINT2 ("  old_regstart: %d\n", 
+			 POINTER_TO_OFFSET (old_regstart[*p]));
+
+          regstart[*p] = d;
+	  DEBUG_PRINT2 ("  regstart: %d\n", POINTER_TO_OFFSET (regstart[*p]));
+
+          IS_ACTIVE (reg_info[*p]) = 1;
+          MATCHED_SOMETHING (reg_info[*p]) = 0;
+          
+          /* This is the new highest active register.  */
+          highest_active_reg = *p;
+          
+          /* If nothing was active before, this is the new lowest active
+             register.  */
+          if (lowest_active_reg == NO_LOWEST_ACTIVE_REG)
+            lowest_active_reg = *p;
+
+          /* Move past the register number and inner group count.  */
+          p += 2;
+	  just_past_start_mem = p;
+          break;
+
+
+        /* The stop_memory opcode represents the end of a group.  Its
+           arguments are the same as start_memory's: the register
+           number, and the number of inner groups.  */
+	case stop_memory:
+	  DEBUG_PRINT3 ("EXECUTING stop_memory %d (%d):\n", *p, p[1]);
+             
+          /* We need to save the string position the last time we were at
+             this close-group operator in case the group is operated
+             upon by a repetition operator, e.g., with `((a*)*(b*)*)*'
+             against `aba'; then we want to ignore where we are now in
+             the string in case this attempt to match fails.  */
+          old_regend[*p] = REG_MATCH_NULL_STRING_P (reg_info[*p])
+                           ? REG_UNSET (regend[*p]) ? d : regend[*p]
+			   : regend[*p];
+	  DEBUG_PRINT2 ("      old_regend: %d\n", 
+			 POINTER_TO_OFFSET (old_regend[*p]));
+
+          regend[*p] = d;
+	  DEBUG_PRINT2 ("      regend: %d\n", POINTER_TO_OFFSET (regend[*p]));
+
+          /* This register isn't active anymore.  */
+          IS_ACTIVE (reg_info[*p]) = 0;
+          
+          /* If this was the only register active, nothing is active
+             anymore.  */
+          if (lowest_active_reg == highest_active_reg)
+            {
+              lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+              highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+            }
+          else
+            { /* We must scan for the new highest active register, since
+                 it isn't necessarily one less than now: consider
+                 (a(b)c(d(e)f)g).  When group 3 ends, after the f), the
+                 new highest active register is 1.  */
+              unsigned char r = *p - 1;
+              while (r > 0 && !IS_ACTIVE (reg_info[r]))
+                r--;
+              
+              /* If we end up at register zero, that means that we saved
+                 the registers as the result of an `on_failure_jump', not
+                 a `start_memory', and we jumped to past the innermost
+                 `stop_memory'.  For example, in ((.)*) we save
+                 registers 1 and 2 as a result of the *, but when we pop
+                 back to the second ), we are at the stop_memory 1.
+                 Thus, nothing is active.  */
+	      if (r == 0)
+                {
+                  lowest_active_reg = NO_LOWEST_ACTIVE_REG;
+                  highest_active_reg = NO_HIGHEST_ACTIVE_REG;
+                }
+              else
+                highest_active_reg = r;
+            }
+          
+          /* If just failed to match something this time around with a
+             group that's operated on by a repetition operator, try to
+             force exit from the ``loop'', and restore the register
+             information for this group that we had before trying this
+             last match.  */
+          if ((!MATCHED_SOMETHING (reg_info[*p])
+               || just_past_start_mem == p - 1)
+	      && (p + 2) < pend)              
+            {
+              boolean is_a_jump_n = false;
+              
+              p1 = p + 2;
+              mcnt = 0;
+              switch ((re_opcode_t) *p1++)
+                {
+                  case jump_n:
+		    is_a_jump_n = true;
+                  case pop_failure_jump:
+		  case maybe_pop_jump:
+		  case jump:
+		  case dummy_failure_jump:
+                    EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+		    if (is_a_jump_n)
+		      p1 += 2;
+                    break;
+                  
+                  default:
+                    /* do nothing */ ;
+                }
+	      p1 += mcnt;
+        
+              /* If the next operation is a jump backwards in the pattern
+	         to an on_failure_jump right before the start_memory
+                 corresponding to this stop_memory, exit from the loop
+                 by forcing a failure after pushing on the stack the
+                 on_failure_jump's jump in the pattern, and d.  */
+              if (mcnt < 0 && (re_opcode_t) *p1 == on_failure_jump
+                  && (re_opcode_t) p1[3] == start_memory && p1[4] == *p)
+		{
+                  /* If this group ever matched anything, then restore
+                     what its registers were before trying this last
+                     failed match, e.g., with `(a*)*b' against `ab' for
+                     regstart[1], and, e.g., with `((a*)*(b*)*)*'
+                     against `aba' for regend[3].
+                     
+                     Also restore the registers for inner groups for,
+                     e.g., `((a*)(b*))*' against `aba' (register 3 would
+                     otherwise get trashed).  */
+                     
+                  if (EVER_MATCHED_SOMETHING (reg_info[*p]))
+		    {
+		      unsigned r; 
+        
+                      EVER_MATCHED_SOMETHING (reg_info[*p]) = 0;
+                      
+		      /* Restore this and inner groups' (if any) registers.  */
+                      for (r = *p; r < *p + *(p + 1); r++)
+                        {
+                          regstart[r] = old_regstart[r];
+
+                          /* xx why this test?  */
+                          if ((long) old_regend[r] >= (long) regstart[r])
+                            regend[r] = old_regend[r];
+                        }     
+                    }
+		  p1++;
+                  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+                  PUSH_FAILURE_POINT (p1 + mcnt, d, -2);
+
+                  goto fail;
+                }
+            }
+          
+          /* Move past the register number and the inner group count.  */
+          p += 2;
+          break;
+
+
+	/* \<digit> has been turned into a `duplicate' command which is
+           followed by the numeric value of <digit> as the register number.  */
+        case duplicate:
+	  {
+	    register const char *d2, *dend2;
+	    int regno = *p++;   /* Get which register to match against.  */
+	    DEBUG_PRINT2 ("EXECUTING duplicate %d.\n", regno);
+
+	    /* Can't back reference a group which we've never matched.  */
+            if (REG_UNSET (regstart[regno]) || REG_UNSET (regend[regno]))
+              goto fail;
+              
+            /* Where in input to try to start matching.  */
+            d2 = regstart[regno];
+            
+            /* Where to stop matching; if both the place to start and
+               the place to stop matching are in the same string, then
+               set to the place to stop, otherwise, for now have to use
+               the end of the first string.  */
+
+            dend2 = ((FIRST_STRING_P (regstart[regno]) 
+		      == FIRST_STRING_P (regend[regno]))
+		     ? regend[regno] : end_match_1);
+	    for (;;)
+	      {
+		/* If necessary, advance to next segment in register
+                   contents.  */
+		while (d2 == dend2)
+		  {
+		    if (dend2 == end_match_2) break;
+		    if (dend2 == regend[regno]) break;
+
+                    /* End of string1 => advance to string2. */
+                    d2 = string2;
+                    dend2 = regend[regno];
+		  }
+		/* At end of register contents => success */
+		if (d2 == dend2) break;
+
+		/* If necessary, advance to next segment in data.  */
+		PREFETCH ();
+
+		/* How many characters left in this segment to match.  */
+		mcnt = dend - d;
+                
+		/* Want how many consecutive characters we can match in
+                   one shot, so, if necessary, adjust the count.  */
+                if (mcnt > dend2 - d2)
+		  mcnt = dend2 - d2;
+                  
+		/* Compare that many; failure if mismatch, else move
+                   past them.  */
+		if (translate 
+                    ? bcmp_translate (d, d2, mcnt, translate) 
+                    : bcmp (d, d2, mcnt))
+		  goto fail;
+		d += mcnt, d2 += mcnt;
+	      }
+	  }
+	  break;
+
+
+        /* begline matches the empty string at the beginning of the string
+           (unless `not_bol' is set in `bufp'), and, if
+           `newline_anchor' is set, after newlines.  */
+	case begline:
+          DEBUG_PRINT1 ("EXECUTING begline.\n");
+          
+          if (AT_STRINGS_BEG (d))
+            {
+              if (!bufp->not_bol) break;
+            }
+          else if (d[-1] == '\n' && bufp->newline_anchor)
+            {
+              break;
+            }
+          /* In all other cases, we fail.  */
+          goto fail;
+
+
+        /* endline is the dual of begline.  */
+	case endline:
+          DEBUG_PRINT1 ("EXECUTING endline.\n");
+
+          if (AT_STRINGS_END (d))
+            {
+              if (!bufp->not_eol) break;
+            }
+          
+          /* We have to ``prefetch'' the next character.  */
+          else if ((d == end1 ? *string2 : *d) == '\n'
+                   && bufp->newline_anchor)
+            {
+              break;
+            }
+          goto fail;
+
+
+	/* Match at the very beginning of the data.  */
+        case begbuf:
+          DEBUG_PRINT1 ("EXECUTING begbuf.\n");
+          if (AT_STRINGS_BEG (d))
+            break;
+          goto fail;
+
+
+	/* Match at the very end of the data.  */
+        case endbuf:
+          DEBUG_PRINT1 ("EXECUTING endbuf.\n");
+	  if (AT_STRINGS_END (d))
+	    break;
+          goto fail;
+
+
+        /* on_failure_keep_string_jump is used to optimize `.*\n'.  It
+           pushes NULL as the value for the string on the stack.  Then
+           `pop_failure_point' will keep the current value for the
+           string, instead of restoring it.  To see why, consider
+           matching `foo\nbar' against `.*\n'.  The .* matches the foo;
+           then the . fails against the \n.  But the next thing we want
+           to do is match the \n against the \n; if we restored the
+           string value, we would be back at the foo.
+           
+           Because this is used only in specific cases, we don't need to
+           check all the things that `on_failure_jump' does, to make
+           sure the right things get saved on the stack.  Hence we don't
+           share its code.  The only reason to push anything on the
+           stack at all is that otherwise we would have to change
+           `anychar's code to do something besides goto fail in this
+           case; that seems worse than this.  */
+        case on_failure_keep_string_jump:
+          DEBUG_PRINT1 ("EXECUTING on_failure_keep_string_jump");
+          
+          EXTRACT_NUMBER_AND_INCR (mcnt, p);
+          DEBUG_PRINT3 (" %d (to 0x%x):\n", mcnt, p + mcnt);
+
+          PUSH_FAILURE_POINT (p + mcnt, NULL, -2);
+          break;
+
+
+	/* Uses of on_failure_jump:
+        
+           Each alternative starts with an on_failure_jump that points
+           to the beginning of the next alternative.  Each alternative
+           except the last ends with a jump that in effect jumps past
+           the rest of the alternatives.  (They really jump to the
+           ending jump of the following alternative, because tensioning
+           these jumps is a hassle.)
+
+           Repeats start with an on_failure_jump that points past both
+           the repetition text and either the following jump or
+           pop_failure_jump back to this on_failure_jump.  */
+	case on_failure_jump:
+        on_failure:
+          DEBUG_PRINT1 ("EXECUTING on_failure_jump");
+
+          EXTRACT_NUMBER_AND_INCR (mcnt, p);
+          DEBUG_PRINT3 (" %d (to 0x%x)", mcnt, p + mcnt);
+
+          /* If this on_failure_jump comes right before a group (i.e.,
+             the original * applied to a group), save the information
+             for that group and all inner ones, so that if we fail back
+             to this point, the group's information will be correct.
+             For example, in \(a*\)*\1, we need the preceding group,
+             and in \(\(a*\)b*\)\2, we need the inner group.  */
+
+          /* We can't use `p' to check ahead because we push
+             a failure point to `p + mcnt' after we do this.  */
+          p1 = p;
+
+          /* We need to skip no_op's before we look for the
+             start_memory in case this on_failure_jump is happening as
+             the result of a completed succeed_n, as in \(a\)\{1,3\}b\1
+             against aba.  */
+          while (p1 < pend && (re_opcode_t) *p1 == no_op)
+            p1++;
+
+          if (p1 < pend && (re_opcode_t) *p1 == start_memory)
+            {
+              /* We have a new highest active register now.  This will
+                 get reset at the start_memory we are about to get to,
+                 but we will have saved all the registers relevant to
+                 this repetition op, as described above.  */
+              highest_active_reg = *(p1 + 1) + *(p1 + 2);
+              if (lowest_active_reg == NO_LOWEST_ACTIVE_REG)
+                lowest_active_reg = *(p1 + 1);
+            }
+
+          DEBUG_PRINT1 (":\n");
+          PUSH_FAILURE_POINT (p + mcnt, d, -2);
+          break;
+
+
+        /* A smart repeat ends with `maybe_pop_jump'.
+	   We change it to either `pop_failure_jump' or `jump'.  */
+        case maybe_pop_jump:
+          EXTRACT_NUMBER_AND_INCR (mcnt, p);
+          DEBUG_PRINT2 ("EXECUTING maybe_pop_jump %d.\n", mcnt);
+          {
+	    register unsigned char *p2 = p;
+
+            /* Compare the beginning of the repeat with what in the
+               pattern follows its end. If we can establish that there
+               is nothing that they would both match, i.e., that we
+               would have to backtrack because of (as in, e.g., `a*a')
+               then we can change to pop_failure_jump, because we'll
+               never have to backtrack.
+               
+               This is not true in the case of alternatives: in
+               `(a|ab)*' we do need to backtrack to the `ab' alternative
+               (e.g., if the string was `ab').  But instead of trying to
+               detect that here, the alternative has put on a dummy
+               failure point which is what we will end up popping.  */
+
+	    /* Skip over open/close-group commands.
+	       If what follows this loop is a ...+ construct,
+	       look at what begins its body, since we will have to
+	       match at least one of that.  */
+	    while (1)
+	      {
+		if (p2 + 2 < pend
+		    && ((re_opcode_t) *p2 == stop_memory
+			|| (re_opcode_t) *p2 == start_memory))
+		  p2 += 3;
+		else if (p2 + 6 < pend
+			 && (re_opcode_t) *p2 == dummy_failure_jump)
+		  p2 += 6;
+		else
+		  break;
+	      }
+
+	    p1 = p + mcnt;
+	    /* p1[0] ... p1[2] are the `on_failure_jump' corresponding
+	       to the `maybe_finalize_jump' of this case.  Examine what 
+	       follows.  */
+
+            /* If we're at the end of the pattern, we can change.  */
+            if (p2 == pend)
+	      {
+		/* Consider what happens when matching ":\(.*\)"
+		   against ":/".  I don't really understand this code
+		   yet.  */
+  	        p[-3] = (unsigned char) pop_failure_jump;
+                DEBUG_PRINT1
+                  ("  End of pattern: change to `pop_failure_jump'.\n");
+              }
+
+            else if ((re_opcode_t) *p2 == exactn
+		     || (bufp->newline_anchor && (re_opcode_t) *p2 == endline))
+	      {
+		register unsigned char c
+                  = *p2 == (unsigned char) endline ? '\n' : p2[2];
+
+                if ((re_opcode_t) p1[3] == exactn && p1[5] != c)
+                  {
+  		    p[-3] = (unsigned char) pop_failure_jump;
+                    DEBUG_PRINT3 ("  %c != %c => pop_failure_jump.\n",
+                                  c, p1[5]);
+                  }
+                  
+		else if ((re_opcode_t) p1[3] == charset
+			 || (re_opcode_t) p1[3] == charset_not)
+		  {
+		    int not = (re_opcode_t) p1[3] == charset_not;
+                    
+		    if (c < (unsigned char) (p1[4] * BYTEWIDTH)
+			&& p1[5 + c / BYTEWIDTH] & (1 << (c % BYTEWIDTH)))
+		      not = !not;
+
+                    /* `not' is equal to 1 if c would match, which means
+                        that we can't change to pop_failure_jump.  */
+		    if (!not)
+                      {
+  		        p[-3] = (unsigned char) pop_failure_jump;
+                        DEBUG_PRINT1 ("  No match => pop_failure_jump.\n");
+                      }
+		  }
+	      }
+            else if ((re_opcode_t) *p2 == charset)
+	      {
+#ifdef DEBUG
+		register unsigned char c
+                  = *p2 == (unsigned char) endline ? '\n' : p2[2];
+#endif
+
+                if ((re_opcode_t) p1[3] == exactn
+		    && ! ((int) p2[1] * BYTEWIDTH > (int) p1[4]
+			  && (p2[1 + p1[4] / BYTEWIDTH]
+			      & (1 << (p1[4] % BYTEWIDTH)))))
+                  {
+  		    p[-3] = (unsigned char) pop_failure_jump;
+                    DEBUG_PRINT3 ("  %c != %c => pop_failure_jump.\n",
+                                  c, p1[5]);
+                  }
+                  
+		else if ((re_opcode_t) p1[3] == charset_not)
+		  {
+		    int idx;
+		    /* We win if the charset_not inside the loop
+		       lists every character listed in the charset after.  */
+		    for (idx = 0; idx < (int) p2[1]; idx++)
+		      if (! (p2[2 + idx] == 0
+			     || (idx < (int) p1[4]
+				 && ((p2[2 + idx] & ~ p1[5 + idx]) == 0))))
+			break;
+
+		    if (idx == p2[1])
+                      {
+  		        p[-3] = (unsigned char) pop_failure_jump;
+                        DEBUG_PRINT1 ("  No match => pop_failure_jump.\n");
+                      }
+		  }
+		else if ((re_opcode_t) p1[3] == charset)
+		  {
+		    int idx;
+		    /* We win if the charset inside the loop
+		       has no overlap with the one after the loop.  */
+		    for (idx = 0;
+			 idx < (int) p2[1] && idx < (int) p1[4];
+			 idx++)
+		      if ((p2[2 + idx] & p1[5 + idx]) != 0)
+			break;
+
+		    if (idx == p2[1] || idx == p1[4])
+                      {
+  		        p[-3] = (unsigned char) pop_failure_jump;
+                        DEBUG_PRINT1 ("  No match => pop_failure_jump.\n");
+                      }
+		  }
+	      }
+	  }
+	  p -= 2;		/* Point at relative address again.  */
+	  if ((re_opcode_t) p[-1] != pop_failure_jump)
+	    {
+	      p[-1] = (unsigned char) jump;
+              DEBUG_PRINT1 ("  Match => jump.\n");
+	      goto unconditional_jump;
+	    }
+        /* Note fall through.  */
+
+
+	/* The end of a simple repeat has a pop_failure_jump back to
+           its matching on_failure_jump, where the latter will push a
+           failure point.  The pop_failure_jump takes off failure
+           points put on by this pop_failure_jump's matching
+           on_failure_jump; we got through the pattern to here from the
+           matching on_failure_jump, so didn't fail.  */
+        case pop_failure_jump:
+          {
+            /* We need to pass separate storage for the lowest and
+               highest registers, even though we don't care about the
+               actual values.  Otherwise, we will restore only one
+               register from the stack, since lowest will == highest in
+               `pop_failure_point'.  */
+            unsigned dummy_low_reg, dummy_high_reg;
+            unsigned char *pdummy;
+            const char *sdummy;
+
+            DEBUG_PRINT1 ("EXECUTING pop_failure_jump.\n");
+            POP_FAILURE_POINT (sdummy, pdummy,
+                               dummy_low_reg, dummy_high_reg,
+                               reg_dummy, reg_dummy, reg_info_dummy);
+          }
+          /* Note fall through.  */
+
+          
+        /* Unconditionally jump (without popping any failure points).  */
+        case jump:
+	unconditional_jump:
+	  EXTRACT_NUMBER_AND_INCR (mcnt, p);	/* Get the amount to jump.  */
+          DEBUG_PRINT2 ("EXECUTING jump %d ", mcnt);
+	  p += mcnt;				/* Do the jump.  */
+          DEBUG_PRINT2 ("(to 0x%x).\n", p);
+	  break;
+
+	
+        /* We need this opcode so we can detect where alternatives end
+           in `group_match_null_string_p' et al.  */
+        case jump_past_alt:
+          DEBUG_PRINT1 ("EXECUTING jump_past_alt.\n");
+          goto unconditional_jump;
+
+
+        /* Normally, the on_failure_jump pushes a failure point, which
+           then gets popped at pop_failure_jump.  We will end up at
+           pop_failure_jump, also, and with a pattern of, say, `a+', we
+           are skipping over the on_failure_jump, so we have to push
+           something meaningless for pop_failure_jump to pop.  */
+        case dummy_failure_jump:
+          DEBUG_PRINT1 ("EXECUTING dummy_failure_jump.\n");
+          /* It doesn't matter what we push for the string here.  What
+             the code at `fail' tests is the value for the pattern.  */
+          PUSH_FAILURE_POINT (0, 0, -2);
+          goto unconditional_jump;
+
+
+        /* At the end of an alternative, we need to push a dummy failure
+           point in case we are followed by a `pop_failure_jump', because
+           we don't want the failure point for the alternative to be
+           popped.  For example, matching `(a|ab)*' against `aab'
+           requires that we match the `ab' alternative.  */
+        case push_dummy_failure:
+          DEBUG_PRINT1 ("EXECUTING push_dummy_failure.\n");
+          /* See comments just above at `dummy_failure_jump' about the
+             two zeroes.  */
+          PUSH_FAILURE_POINT (0, 0, -2);
+          break;
+
+        /* Have to succeed matching what follows at least n times.
+           After that, handle like `on_failure_jump'.  */
+        case succeed_n: 
+          EXTRACT_NUMBER (mcnt, p + 2);
+          DEBUG_PRINT2 ("EXECUTING succeed_n %d.\n", mcnt);
+
+          assert (mcnt >= 0);
+          /* Originally, this is how many times we HAVE to succeed.  */
+          if (mcnt > 0)
+            {
+               mcnt--;
+	       p += 2;
+               STORE_NUMBER_AND_INCR (p, mcnt);
+               DEBUG_PRINT3 ("  Setting 0x%x to %d.\n", p, mcnt);
+            }
+	  else if (mcnt == 0)
+            {
+              DEBUG_PRINT2 ("  Setting two bytes from 0x%x to no_op.\n", p+2);
+	      p[2] = (unsigned char) no_op;
+              p[3] = (unsigned char) no_op;
+              goto on_failure;
+            }
+          break;
+        
+        case jump_n: 
+          EXTRACT_NUMBER (mcnt, p + 2);
+          DEBUG_PRINT2 ("EXECUTING jump_n %d.\n", mcnt);
+
+          /* Originally, this is how many times we CAN jump.  */
+          if (mcnt)
+            {
+               mcnt--;
+               STORE_NUMBER (p + 2, mcnt);
+	       goto unconditional_jump;	     
+            }
+          /* If don't have to jump any more, skip over the rest of command.  */
+	  else      
+	    p += 4;		     
+          break;
+        
+	case set_number_at:
+	  {
+            DEBUG_PRINT1 ("EXECUTING set_number_at.\n");
+
+            EXTRACT_NUMBER_AND_INCR (mcnt, p);
+            p1 = p + mcnt;
+            EXTRACT_NUMBER_AND_INCR (mcnt, p);
+            DEBUG_PRINT3 ("  Setting 0x%x to %d.\n", p1, mcnt);
+	    STORE_NUMBER (p1, mcnt);
+            break;
+          }
+
+        case wordbound:
+          DEBUG_PRINT1 ("EXECUTING wordbound.\n");
+          if (AT_WORD_BOUNDARY (d))
+	    break;
+          goto fail;
+
+	case notwordbound:
+          DEBUG_PRINT1 ("EXECUTING notwordbound.\n");
+	  if (AT_WORD_BOUNDARY (d))
+	    goto fail;
+          break;
+
+	case wordbeg:
+          DEBUG_PRINT1 ("EXECUTING wordbeg.\n");
+	  if (WORDCHAR_P (d) && (AT_STRINGS_BEG (d) || !WORDCHAR_P (d - 1)))
+	    break;
+          goto fail;
+
+	case wordend:
+          DEBUG_PRINT1 ("EXECUTING wordend.\n");
+	  if (!AT_STRINGS_BEG (d) && WORDCHAR_P (d - 1)
+              && (!WORDCHAR_P (d) || AT_STRINGS_END (d)))
+	    break;
+          goto fail;
+
+#ifdef emacs
+  	case before_dot:
+          DEBUG_PRINT1 ("EXECUTING before_dot.\n");
+ 	  if (PTR_CHAR_POS ((unsigned char *) d) >= point)
+  	    goto fail;
+  	  break;
+  
+  	case at_dot:
+          DEBUG_PRINT1 ("EXECUTING at_dot.\n");
+ 	  if (PTR_CHAR_POS ((unsigned char *) d) != point)
+  	    goto fail;
+  	  break;
+  
+  	case after_dot:
+          DEBUG_PRINT1 ("EXECUTING after_dot.\n");
+          if (PTR_CHAR_POS ((unsigned char *) d) <= point)
+  	    goto fail;
+  	  break;
+#if 0 /* not emacs19 */
+	case at_dot:
+          DEBUG_PRINT1 ("EXECUTING at_dot.\n");
+	  if (PTR_CHAR_POS ((unsigned char *) d) + 1 != point)
+	    goto fail;
+	  break;
+#endif /* not emacs19 */
+
+	case syntaxspec:
+          DEBUG_PRINT2 ("EXECUTING syntaxspec %d.\n", mcnt);
+	  mcnt = *p++;
+	  goto matchsyntax;
+
+        case wordchar:
+          DEBUG_PRINT1 ("EXECUTING Emacs wordchar.\n");
+	  mcnt = (int) Sword;
+        matchsyntax:
+	  PREFETCH ();
+	  /* Can't use *d++ here; SYNTAX may be an unsafe macro.  */
+	  d++;
+	  if (SYNTAX (d[-1]) != (enum syntaxcode) mcnt)
+	    goto fail;
+          SET_REGS_MATCHED ();
+	  break;
+
+	case notsyntaxspec:
+          DEBUG_PRINT2 ("EXECUTING notsyntaxspec %d.\n", mcnt);
+	  mcnt = *p++;
+	  goto matchnotsyntax;
+
+        case notwordchar:
+          DEBUG_PRINT1 ("EXECUTING Emacs notwordchar.\n");
+	  mcnt = (int) Sword;
+        matchnotsyntax:
+	  PREFETCH ();
+	  /* Can't use *d++ here; SYNTAX may be an unsafe macro.  */
+	  d++;
+	  if (SYNTAX (d[-1]) == (enum syntaxcode) mcnt)
+	    goto fail;
+	  SET_REGS_MATCHED ();
+          break;
+
+#else /* not emacs */
+	case wordchar:
+          DEBUG_PRINT1 ("EXECUTING non-Emacs wordchar.\n");
+	  PREFETCH ();
+          if (!WORDCHAR_P (d))
+            goto fail;
+	  SET_REGS_MATCHED ();
+          d++;
+	  break;
+	  
+	case notwordchar:
+          DEBUG_PRINT1 ("EXECUTING non-Emacs notwordchar.\n");
+	  PREFETCH ();
+	  if (WORDCHAR_P (d))
+            goto fail;
+          SET_REGS_MATCHED ();
+          d++;
+	  break;
+#endif /* not emacs */
+          
+        default:
+          abort ();
+	}
+      continue;  /* Successfully executed one pattern command; keep going.  */
+
+
+    /* We goto here if a matching operation fails. */
+    fail:
+      if (!FAIL_STACK_EMPTY ())
+	{ /* A restart point is known.  Restore to that state.  */
+          DEBUG_PRINT1 ("\nFAIL:\n");
+          POP_FAILURE_POINT (d, p,
+                             lowest_active_reg, highest_active_reg,
+                             regstart, regend, reg_info);
+
+          /* If this failure point is a dummy, try the next one.  */
+          if (!p)
+	    goto fail;
+
+          /* If we failed to the end of the pattern, don't examine *p.  */
+	  assert (p <= pend);
+          if (p < pend)
+            {
+              boolean is_a_jump_n = false;
+              
+              /* If failed to a backwards jump that's part of a repetition
+                 loop, need to pop this failure point and use the next one.  */
+              switch ((re_opcode_t) *p)
+                {
+                case jump_n:
+                  is_a_jump_n = true;
+                case maybe_pop_jump:
+                case pop_failure_jump:
+                case jump:
+                  p1 = p + 1;
+                  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+                  p1 += mcnt;	
+
+                  if ((is_a_jump_n && (re_opcode_t) *p1 == succeed_n)
+                      || (!is_a_jump_n
+                          && (re_opcode_t) *p1 == on_failure_jump))
+                    goto fail;
+                  break;
+                default:
+                  /* do nothing */ ;
+                }
+            }
+
+          if (d >= string1 && d <= end1)
+	    dend = end_match_1;
+        }
+      else
+        break;   /* Matching at this starting point really fails.  */
+    } /* for (;;) */
+
+  if (best_regs_set)
+    goto restore_best_regs;
+
+  FREE_VARIABLES ();
+
+  return -1;         			/* Failure to match.  */
+} /* re_match_2 */
+
+/* Subroutine definitions for re_match_2.  */
+
+
+/* We are passed P pointing to a register number after a start_memory.
+   
+   Return true if the pattern up to the corresponding stop_memory can
+   match the empty string, and false otherwise.
+   
+   If we find the matching stop_memory, sets P to point to one past its number.
+   Otherwise, sets P to an undefined byte less than or equal to END.
+
+   We don't handle duplicates properly (yet).  */
+
+static boolean
+group_match_null_string_p (p, end, reg_info)
+    unsigned char **p, *end;
+    register_info_type *reg_info;
+{
+  int mcnt;
+  /* Point to after the args to the start_memory.  */
+  unsigned char *p1 = *p + 2;
+  
+  while (p1 < end)
+    {
+      /* Skip over opcodes that can match nothing, and return true or
+	 false, as appropriate, when we get to one that can't, or to the
+         matching stop_memory.  */
+      
+      switch ((re_opcode_t) *p1)
+        {
+        /* Could be either a loop or a series of alternatives.  */
+        case on_failure_jump:
+          p1++;
+          EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+          
+          /* If the next operation is not a jump backwards in the
+	     pattern.  */
+
+	  if (mcnt >= 0)
+	    {
+              /* Go through the on_failure_jumps of the alternatives,
+                 seeing if any of the alternatives cannot match nothing.
+                 The last alternative starts with only a jump,
+                 whereas the rest start with on_failure_jump and end
+                 with a jump, e.g., here is the pattern for `a|b|c':
+
+                 /on_failure_jump/0/6/exactn/1/a/jump_past_alt/0/6
+                 /on_failure_jump/0/6/exactn/1/b/jump_past_alt/0/3
+                 /exactn/1/c						
+
+                 So, we have to first go through the first (n-1)
+                 alternatives and then deal with the last one separately.  */
+
+
+              /* Deal with the first (n-1) alternatives, which start
+                 with an on_failure_jump (see above) that jumps to right
+                 past a jump_past_alt.  */
+
+              while ((re_opcode_t) p1[mcnt-3] == jump_past_alt)
+                {
+                  /* `mcnt' holds how many bytes long the alternative
+                     is, including the ending `jump_past_alt' and
+                     its number.  */
+
+                  if (!alt_match_null_string_p (p1, p1 + mcnt - 3, 
+				                      reg_info))
+                    return false;
+
+                  /* Move to right after this alternative, including the
+		     jump_past_alt.  */
+                  p1 += mcnt;	
+
+                  /* Break if it's the beginning of an n-th alternative
+                     that doesn't begin with an on_failure_jump.  */
+                  if ((re_opcode_t) *p1 != on_failure_jump)
+                    break;
+		
+		  /* Still have to check that it's not an n-th
+		     alternative that starts with an on_failure_jump.  */
+		  p1++;
+                  EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+                  if ((re_opcode_t) p1[mcnt-3] != jump_past_alt)
+                    {
+		      /* Get to the beginning of the n-th alternative.  */
+                      p1 -= 3;
+                      break;
+                    }
+                }
+
+              /* Deal with the last alternative: go back and get number
+                 of the `jump_past_alt' just before it.  `mcnt' contains
+                 the length of the alternative.  */
+              EXTRACT_NUMBER (mcnt, p1 - 2);
+
+              if (!alt_match_null_string_p (p1, p1 + mcnt, reg_info))
+                return false;
+
+              p1 += mcnt;	/* Get past the n-th alternative.  */
+            } /* if mcnt > 0 */
+          break;
+
+          
+        case stop_memory:
+	  assert (p1[1] == **p);
+          *p = p1 + 2;
+          return true;
+
+        
+        default: 
+          if (!common_op_match_null_string_p (&p1, end, reg_info))
+            return false;
+        }
+    } /* while p1 < end */
+
+  return false;
+} /* group_match_null_string_p */
+
+
+/* Similar to group_match_null_string_p, but doesn't deal with alternatives:
+   It expects P to be the first byte of a single alternative and END one
+   byte past the last. The alternative can contain groups.  */
+   
+static boolean
+alt_match_null_string_p (p, end, reg_info)
+    unsigned char *p, *end;
+    register_info_type *reg_info;
+{
+  int mcnt;
+  unsigned char *p1 = p;
+  
+  while (p1 < end)
+    {
+      /* Skip over opcodes that can match nothing, and break when we get 
+         to one that can't.  */
+      
+      switch ((re_opcode_t) *p1)
+        {
+	/* It's a loop.  */
+        case on_failure_jump:
+          p1++;
+          EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+          p1 += mcnt;
+          break;
+          
+	default: 
+          if (!common_op_match_null_string_p (&p1, end, reg_info))
+            return false;
+        }
+    }  /* while p1 < end */
+
+  return true;
+} /* alt_match_null_string_p */
+
+
+/* Deals with the ops common to group_match_null_string_p and
+   alt_match_null_string_p.  
+   
+   Sets P to one after the op and its arguments, if any.  */
+
+static boolean
+common_op_match_null_string_p (p, end, reg_info)
+    unsigned char **p, *end;
+    register_info_type *reg_info;
+{
+  int mcnt;
+  boolean ret;
+  int reg_no;
+  unsigned char *p1 = *p;
+
+  switch ((re_opcode_t) *p1++)
+    {
+    case no_op:
+    case begline:
+    case endline:
+    case begbuf:
+    case endbuf:
+    case wordbeg:
+    case wordend:
+    case wordbound:
+    case notwordbound:
+#ifdef emacs
+    case before_dot:
+    case at_dot:
+    case after_dot:
+#endif
+      break;
+
+    case start_memory:
+      reg_no = *p1;
+      assert (reg_no > 0 && reg_no <= MAX_REGNUM);
+      ret = group_match_null_string_p (&p1, end, reg_info);
+      
+      /* Have to set this here in case we're checking a group which
+         contains a group and a back reference to it.  */
+
+      if (REG_MATCH_NULL_STRING_P (reg_info[reg_no]) == MATCH_NULL_UNSET_VALUE)
+        REG_MATCH_NULL_STRING_P (reg_info[reg_no]) = ret;
+
+      if (!ret)
+        return false;
+      break;
+          
+    /* If this is an optimized succeed_n for zero times, make the jump.  */
+    case jump:
+      EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+      if (mcnt >= 0)
+        p1 += mcnt;
+      else
+        return false;
+      break;
+
+    case succeed_n:
+      /* Get to the number of times to succeed.  */
+      p1 += 2;		
+      EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+
+      if (mcnt == 0)
+        {
+          p1 -= 4;
+          EXTRACT_NUMBER_AND_INCR (mcnt, p1);
+          p1 += mcnt;
+        }
+      else
+        return false;
+      break;
+
+    case duplicate: 
+      if (!REG_MATCH_NULL_STRING_P (reg_info[*p1]))
+        return false;
+      break;
+
+    case set_number_at:
+      p1 += 4;
+
+    default:
+      /* All other opcodes mean we cannot match the empty string.  */
+      return false;
+  }
+
+  *p = p1;
+  return true;
+} /* common_op_match_null_string_p */
+
+
+/* Return zero if TRANSLATE[S1] and TRANSLATE[S2] are identical for LEN
+   bytes; nonzero otherwise.  */
+   
+static int
+bcmp_translate (s1, s2, len, translate)
+     unsigned char *s1, *s2;
+     register int len;
+     char *translate;
+{
+  register unsigned char *p1 = s1, *p2 = s2;
+  while (len)
+    {
+      if (translate[*p1++] != translate[*p2++]) return 1;
+      len--;
+    }
+  return 0;
+}
+
+/* Entry points for GNU code.  */
+
+/* re_compile_pattern is the GNU regular expression compiler: it
+   compiles PATTERN (of length SIZE) and puts the result in BUFP.
+   Returns 0 if the pattern was valid, otherwise an error string.
+   
+   Assumes the `allocated' (and perhaps `buffer') and `translate' fields
+   are set in BUFP on entry.
+   
+   We call regex_compile to do the actual compilation.  */
+
+const char *
+re_compile_pattern (pattern, length, bufp)
+     const char *pattern;
+     int length;
+     struct re_pattern_buffer *bufp;
+{
+  reg_errcode_t ret;
+  
+  /* GNU code is written to assume at least RE_NREGS registers will be set
+     (and at least one extra will be -1).  */
+  bufp->regs_allocated = REGS_UNALLOCATED;
+  
+  /* And GNU code determines whether or not to get register information
+     by passing null for the REGS argument to re_match, etc., not by
+     setting no_sub.  */
+  bufp->no_sub = 0;
+  
+  /* Match anchors at newline.  */
+  bufp->newline_anchor = 1;
+  
+  ret = regex_compile (pattern, length, re_syntax_options, bufp);
+
+  return re_error_msg[(int) ret];
+}     
+
+/* Entry points compatible with 4.2 BSD regex library.  We don't define
+   them if this is an Emacs or POSIX compilation.  */
+
+#if !defined (emacs) && !defined (_POSIX_SOURCE)
+
+/* BSD has one and only one pattern buffer.  */
+static struct re_pattern_buffer re_comp_buf;
+
+char *
+re_comp (s)
+    const char *s;
+{
+  reg_errcode_t ret;
+  
+  if (!s)
+    {
+      if (!re_comp_buf.buffer)
+	return "No previous regular expression";
+      return 0;
+    }
+
+  if (!re_comp_buf.buffer)
+    {
+      re_comp_buf.buffer = (unsigned char *) malloc (200);
+      if (re_comp_buf.buffer == NULL)
+        return "Memory exhausted";
+      re_comp_buf.allocated = 200;
+
+      re_comp_buf.fastmap = (char *) malloc (1 << BYTEWIDTH);
+      if (re_comp_buf.fastmap == NULL)
+	return "Memory exhausted";
+    }
+
+  /* Since `re_exec' always passes NULL for the `regs' argument, we
+     don't need to initialize the pattern buffer fields which affect it.  */
+
+  /* Match anchors at newlines.  */
+  re_comp_buf.newline_anchor = 1;
+
+  ret = regex_compile (s, strlen (s), re_syntax_options, &re_comp_buf);
+  
+  /* Yes, we're discarding `const' here.  */
+  return (char *) re_error_msg[(int) ret];
+}
+
+
+int
+re_exec (s)
+    const char *s;
+{
+  const int len = strlen (s);
+  return
+    0 <= re_search (&re_comp_buf, s, len, 0, len, (struct re_registers *) 0);
+}
+#endif /* not emacs and not _POSIX_SOURCE */
+
+/* POSIX.2 functions.  Don't define these for Emacs.  */
+
+#ifndef emacs
+
+/* regcomp takes a regular expression as a string and compiles it.
+
+   PREG is a regex_t *.  We do not expect any fields to be initialized,
+   since POSIX says we shouldn't.  Thus, we set
+
+     `buffer' to the compiled pattern;
+     `used' to the length of the compiled pattern;
+     `syntax' to RE_SYNTAX_POSIX_EXTENDED if the
+       REG_EXTENDED bit in CFLAGS is set; otherwise, to
+       RE_SYNTAX_POSIX_BASIC;
+     `newline_anchor' to REG_NEWLINE being set in CFLAGS;
+     `fastmap' and `fastmap_accurate' to zero;
+     `re_nsub' to the number of subexpressions in PATTERN.
+
+   PATTERN is the address of the pattern string.
+
+   CFLAGS is a series of bits which affect compilation.
+
+     If REG_EXTENDED is set, we use POSIX extended syntax; otherwise, we
+     use POSIX basic syntax.
+
+     If REG_NEWLINE is set, then . and [^...] don't match newline.
+     Also, regexec will try a match beginning after every newline.
+
+     If REG_ICASE is set, then we considers upper- and lowercase
+     versions of letters to be equivalent when matching.
+
+     If REG_NOSUB is set, then when PREG is passed to regexec, that
+     routine will report only success or failure, and nothing about the
+     registers.
+
+   It returns 0 if it succeeds, nonzero if it doesn't.  (See regex.h for
+   the return codes and their meanings.)  */
+
+int
+regcomp (preg, pattern, cflags)
+    regex_t *preg;
+    const char *pattern; 
+    int cflags;
+{
+  reg_errcode_t ret;
+  unsigned syntax
+    = (cflags & REG_EXTENDED) ?
+      RE_SYNTAX_POSIX_EXTENDED : RE_SYNTAX_POSIX_BASIC;
+
+  /* regex_compile will allocate the space for the compiled pattern.  */
+  preg->buffer = 0;
+  preg->allocated = 0;
+  preg->used = 0;
+  
+  /* Don't bother to use a fastmap when searching.  This simplifies the
+     REG_NEWLINE case: if we used a fastmap, we'd have to put all the
+     characters after newlines into the fastmap.  This way, we just try
+     every character.  */
+  preg->fastmap = 0;
+  
+  if (cflags & REG_ICASE)
+    {
+      unsigned i;
+      
+      preg->translate = (char *) malloc (CHAR_SET_SIZE);
+      if (preg->translate == NULL)
+        return (int) REG_ESPACE;
+
+      /* Map uppercase characters to corresponding lowercase ones.  */
+      for (i = 0; i < CHAR_SET_SIZE; i++)
+        preg->translate[i] = ISUPPER (i) ? tolower (i) : i;
+    }
+  else
+    preg->translate = NULL;
+
+  /* If REG_NEWLINE is set, newlines are treated differently.  */
+  if (cflags & REG_NEWLINE)
+    { /* REG_NEWLINE implies neither . nor [^...] match newline.  */
+      syntax &= ~RE_DOT_NEWLINE;
+      syntax |= RE_HAT_LISTS_NOT_NEWLINE;
+      /* It also changes the matching behavior.  */
+      preg->newline_anchor = 1;
+    }
+  else
+    preg->newline_anchor = 0;
+
+  preg->no_sub = !!(cflags & REG_NOSUB);
+
+  /* POSIX says a null character in the pattern terminates it, so we 
+     can use strlen here in compiling the pattern.  */
+  ret = regex_compile (pattern, strlen (pattern), syntax, preg);
+  
+  /* POSIX doesn't distinguish between an unmatched open-group and an
+     unmatched close-group: both are REG_EPAREN.  */
+  if (ret == REG_ERPAREN) ret = REG_EPAREN;
+  
+  return (int) ret;
+}
+
+
+/* regexec searches for a given pattern, specified by PREG, in the
+   string STRING.
+   
+   If NMATCH is zero or REG_NOSUB was set in the cflags argument to
+   `regcomp', we ignore PMATCH.  Otherwise, we assume PMATCH has at
+   least NMATCH elements, and we set them to the offsets of the
+   corresponding matched substrings.
+   
+   EFLAGS specifies `execution flags' which affect matching: if
+   REG_NOTBOL is set, then ^ does not match at the beginning of the
+   string; if REG_NOTEOL is set, then $ does not match at the end.
+   
+   We return 0 if we find a match and REG_NOMATCH if not.  */
+
+int
+regexec (preg, string, nmatch, pmatch, eflags)
+    const regex_t *preg;
+    const char *string; 
+    size_t nmatch; 
+    regmatch_t pmatch[]; 
+    int eflags;
+{
+  int ret;
+  struct re_registers regs;
+  regex_t private_preg;
+  int len = strlen (string);
+  boolean want_reg_info = !preg->no_sub && nmatch > 0;
+
+  private_preg = *preg;
+  
+  private_preg.not_bol = !!(eflags & REG_NOTBOL);
+  private_preg.not_eol = !!(eflags & REG_NOTEOL);
+  
+  /* The user has told us exactly how many registers to return
+     information about, via `nmatch'.  We have to pass that on to the
+     matching routines.  */
+  private_preg.regs_allocated = REGS_FIXED;
+  
+  if (want_reg_info)
+    {
+      regs.num_regs = nmatch;
+      regs.start = TALLOC (nmatch, regoff_t);
+      regs.end = TALLOC (nmatch, regoff_t);
+      if (regs.start == NULL || regs.end == NULL)
+        return (int) REG_NOMATCH;
+    }
+
+  /* Perform the searching operation.  */
+  ret = re_search (&private_preg, string, len,
+                   /* start: */ 0, /* range: */ len,
+                   want_reg_info ? &regs : (struct re_registers *) 0);
+  
+  /* Copy the register information to the POSIX structure.  */
+  if (want_reg_info)
+    {
+      if (ret >= 0)
+        {
+          unsigned r;
+
+          for (r = 0; r < nmatch; r++)
+            {
+              pmatch[r].rm_so = regs.start[r];
+              pmatch[r].rm_eo = regs.end[r];
+            }
+        }
+
+      /* If we needed the temporary register info, free the space now.  */
+      free (regs.start);
+      free (regs.end);
+    }
+
+  /* We want zero return to mean success, unlike `re_search'.  */
+  return ret >= 0 ? (int) REG_NOERROR : (int) REG_NOMATCH;
+}
+
+
+/* Returns a message corresponding to an error code, ERRCODE, returned
+   from either regcomp or regexec.   We don't use PREG here.  */
+
+size_t
+regerror (errcode, preg, errbuf, errbuf_size)
+    int errcode;
+    const regex_t *preg;
+    char *errbuf;
+    size_t errbuf_size;
+{
+  const char *msg;
+  size_t msg_size;
+
+  if (errcode < 0
+      || errcode >= (sizeof (re_error_msg) / sizeof (re_error_msg[0])))
+    /* Only error codes returned by the rest of the code should be passed 
+       to this routine.  If we are given anything else, or if other regex
+       code generates an invalid error code, then the program has a bug.
+       Dump core so we can fix it.  */
+    abort ();
+
+  msg = re_error_msg[errcode];
+
+  /* POSIX doesn't require that we do anything in this case, but why
+     not be nice.  */
+  if (! msg)
+    msg = "Success";
+
+  msg_size = strlen (msg) + 1; /* Includes the null.  */
+  
+  if (errbuf_size != 0)
+    {
+      if (msg_size > errbuf_size)
+        {
+          strncpy (errbuf, msg, errbuf_size - 1);
+          errbuf[errbuf_size - 1] = 0;
+        }
+      else
+        strcpy (errbuf, msg);
+    }
+
+  return msg_size;
+}
+
+
+/* Free dynamically allocated space used by PREG.  */
+
+void
+regfree (preg)
+    regex_t *preg;
+{
+  if (preg->buffer != NULL)
+    free (preg->buffer);
+  preg->buffer = NULL;
+  
+  preg->allocated = 0;
+  preg->used = 0;
+
+  if (preg->fastmap != NULL)
+    free (preg->fastmap);
+  preg->fastmap = NULL;
+  preg->fastmap_accurate = 0;
+
+  if (preg->translate != NULL)
+    free (preg->translate);
+  preg->translate = NULL;
+}
+
+#endif /* not emacs  */
+
+/*
+Local variables:
+make-backup-files: t
+version-control: t
+trim-versions-without-asking: nil
+End:
+*/
diff --git a/gnu/usr.bin/diff/regex.h b/gnu/usr.bin/diff/regex.h
new file mode 100644
index 00000000000..a495005ce93
--- /dev/null
+++ b/gnu/usr.bin/diff/regex.h
@@ -0,0 +1,490 @@
+/* Definitions for data structures and routines for the regular
+   expression library, version 0.12.
+
+   Copyright (C) 1985, 89, 90, 91, 92, 1993 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#ifndef __REGEXP_LIBRARY_H__
+#define __REGEXP_LIBRARY_H__
+
+/* POSIX says that <sys/types.h> must be included (by the caller) before
+   <regex.h>.  */
+
+#ifdef VMS
+/* VMS doesn't have `size_t' in <sys/types.h>, even though POSIX says it
+   should be there.  */
+#include <stddef.h>
+#endif
+
+
+/* The following bits are used to determine the regexp syntax we
+   recognize.  The set/not-set meanings are chosen so that Emacs syntax
+   remains the value 0.  The bits are given in alphabetical order, and
+   the definitions shifted by one from the previous bit; thus, when we
+   add or remove a bit, only one other definition need change.  */
+typedef unsigned reg_syntax_t;
+
+/* If this bit is not set, then \ inside a bracket expression is literal.
+   If set, then such a \ quotes the following character.  */
+#define RE_BACKSLASH_ESCAPE_IN_LISTS (1)
+
+/* If this bit is not set, then + and ? are operators, and \+ and \? are
+     literals. 
+   If set, then \+ and \? are operators and + and ? are literals.  */
+#define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
+
+/* If this bit is set, then character classes are supported.  They are:
+     [:alpha:], [:upper:], [:lower:],  [:digit:], [:alnum:], [:xdigit:],
+     [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
+   If not set, then character classes are not supported.  */
+#define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
+
+/* If this bit is set, then ^ and $ are always anchors (outside bracket
+     expressions, of course).
+   If this bit is not set, then it depends:
+        ^  is an anchor if it is at the beginning of a regular
+           expression or after an open-group or an alternation operator;
+        $  is an anchor if it is at the end of a regular expression, or
+           before a close-group or an alternation operator.  
+
+   This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
+   POSIX draft 11.2 says that * etc. in leading positions is undefined.
+   We already implemented a previous draft which made those constructs
+   invalid, though, so we haven't changed the code back.  */
+#define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
+
+/* If this bit is set, then special characters are always special
+     regardless of where they are in the pattern.
+   If this bit is not set, then special characters are special only in
+     some contexts; otherwise they are ordinary.  Specifically, 
+     * + ? and intervals are only special when not after the beginning,
+     open-group, or alternation operator.  */
+#define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
+
+/* If this bit is set, then *, +, ?, and { cannot be first in an re or
+     immediately after an alternation or begin-group operator.  */
+#define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
+
+/* If this bit is set, then . matches newline.
+   If not set, then it doesn't.  */
+#define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
+
+/* If this bit is set, then . doesn't match NUL.
+   If not set, then it does.  */
+#define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
+
+/* If this bit is set, nonmatching lists [^...] do not match newline.
+   If not set, they do.  */
+#define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
+
+/* If this bit is set, either \{...\} or {...} defines an
+     interval, depending on RE_NO_BK_BRACES. 
+   If not set, \{, \}, {, and } are literals.  */
+#define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
+
+/* If this bit is set, +, ? and | aren't recognized as operators.
+   If not set, they are.  */
+#define RE_LIMITED_OPS (RE_INTERVALS << 1)
+
+/* If this bit is set, newline is an alternation operator.
+   If not set, newline is literal.  */
+#define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
+
+/* If this bit is set, then `{...}' defines an interval, and \{ and \}
+     are literals.
+  If not set, then `\{...\}' defines an interval.  */
+#define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
+
+/* If this bit is set, (...) defines a group, and \( and \) are literals.
+   If not set, \(...\) defines a group, and ( and ) are literals.  */
+#define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
+
+/* If this bit is set, then \<digit> matches <digit>.
+   If not set, then \<digit> is a back-reference.  */
+#define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
+
+/* If this bit is set, then | is an alternation operator, and \| is literal. 
+   If not set, then \| is an alternation operator, and | is literal.  */
+#define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
+
+/* If this bit is set, then an ending range point collating higher
+     than the starting range point, as in [z-a], is invalid.
+   If not set, then when ending range point collates higher than the
+     starting range point, the range is ignored.  */
+#define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
+
+/* If this bit is set, then an unmatched ) is ordinary.
+   If not set, then an unmatched ) is invalid.  */
+#define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)
+
+/* This global variable defines the particular regexp syntax to use (for
+   some interfaces).  When a regexp is compiled, the syntax used is
+   stored in the pattern buffer, so changing this does not affect
+   already-compiled regexps.  */
+extern reg_syntax_t re_syntax_options;
+
+/* Define combinations of the above bits for the standard possibilities.
+   (The [[[ comments delimit what gets put into the Texinfo file, so
+   don't delete them!)  */ 
+/* [[[begin syntaxes]]] */
+#define RE_SYNTAX_EMACS 0
+
+#define RE_SYNTAX_AWK							\
+  (RE_BACKSLASH_ESCAPE_IN_LISTS | RE_DOT_NOT_NULL			\
+   | RE_NO_BK_PARENS            | RE_NO_BK_REFS				\
+   | RE_NO_BK_VBAR               | RE_NO_EMPTY_RANGES			\
+   | RE_UNMATCHED_RIGHT_PAREN_ORD)
+
+#define RE_SYNTAX_POSIX_AWK 						\
+  (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS)
+
+#define RE_SYNTAX_GREP							\
+  (RE_BK_PLUS_QM              | RE_CHAR_CLASSES				\
+   | RE_HAT_LISTS_NOT_NEWLINE | RE_INTERVALS				\
+   | RE_NEWLINE_ALT)
+
+#define RE_SYNTAX_EGREP							\
+  (RE_CHAR_CLASSES        | RE_CONTEXT_INDEP_ANCHORS			\
+   | RE_CONTEXT_INDEP_OPS | RE_HAT_LISTS_NOT_NEWLINE			\
+   | RE_NEWLINE_ALT       | RE_NO_BK_PARENS				\
+   | RE_NO_BK_VBAR)
+
+#define RE_SYNTAX_POSIX_EGREP						\
+  (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES)
+
+/* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
+#define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC
+
+#define RE_SYNTAX_SED RE_SYNTAX_POSIX_BASIC
+
+/* Syntax bits common to both basic and extended POSIX regex syntax.  */
+#define _RE_SYNTAX_POSIX_COMMON						\
+  (RE_CHAR_CLASSES | RE_DOT_NEWLINE      | RE_DOT_NOT_NULL		\
+   | RE_INTERVALS  | RE_NO_EMPTY_RANGES)
+
+#define RE_SYNTAX_POSIX_BASIC						\
+  (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM)
+
+/* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
+   RE_LIMITED_OPS, i.e., \? \+ \| are not recognized.  Actually, this
+   isn't minimal, since other operators, such as \`, aren't disabled.  */
+#define RE_SYNTAX_POSIX_MINIMAL_BASIC					\
+  (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)
+
+#define RE_SYNTAX_POSIX_EXTENDED					\
+  (_RE_SYNTAX_POSIX_COMMON | RE_CONTEXT_INDEP_ANCHORS			\
+   | RE_CONTEXT_INDEP_OPS  | RE_NO_BK_BRACES				\
+   | RE_NO_BK_PARENS       | RE_NO_BK_VBAR				\
+   | RE_UNMATCHED_RIGHT_PAREN_ORD)
+
+/* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INVALID_OPS
+   replaces RE_CONTEXT_INDEP_OPS and RE_NO_BK_REFS is added.  */
+#define RE_SYNTAX_POSIX_MINIMAL_EXTENDED				\
+  (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS			\
+   | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES				\
+   | RE_NO_BK_PARENS        | RE_NO_BK_REFS				\
+   | RE_NO_BK_VBAR	    | RE_UNMATCHED_RIGHT_PAREN_ORD)
+/* [[[end syntaxes]]] */
+
+/* Maximum number of duplicates an interval can allow.  Some systems
+   (erroneously) define this in other header files, but we want our
+   value, so remove any previous define.  */
+#ifdef RE_DUP_MAX
+#undef RE_DUP_MAX
+#endif
+#define RE_DUP_MAX ((1 << 15) - 1) 
+
+
+/* POSIX `cflags' bits (i.e., information for `regcomp').  */
+
+/* If this bit is set, then use extended regular expression syntax.
+   If not set, then use basic regular expression syntax.  */
+#define REG_EXTENDED 1
+
+/* If this bit is set, then ignore case when matching.
+   If not set, then case is significant.  */
+#define REG_ICASE (REG_EXTENDED << 1)
+ 
+/* If this bit is set, then anchors do not match at newline
+     characters in the string.
+   If not set, then anchors do match at newlines.  */
+#define REG_NEWLINE (REG_ICASE << 1)
+
+/* If this bit is set, then report only success or fail in regexec.
+   If not set, then returns differ between not matching and errors.  */
+#define REG_NOSUB (REG_NEWLINE << 1)
+
+
+/* POSIX `eflags' bits (i.e., information for regexec).  */
+
+/* If this bit is set, then the beginning-of-line operator doesn't match
+     the beginning of the string (presumably because it's not the
+     beginning of a line).
+   If not set, then the beginning-of-line operator does match the
+     beginning of the string.  */
+#define REG_NOTBOL 1
+
+/* Like REG_NOTBOL, except for the end-of-line.  */
+#define REG_NOTEOL (1 << 1)
+
+
+/* If any error codes are removed, changed, or added, update the
+   `re_error_msg' table in regex.c.  */
+typedef enum
+{
+  REG_NOERROR = 0,	/* Success.  */
+  REG_NOMATCH,		/* Didn't find a match (for regexec).  */
+
+  /* POSIX regcomp return error codes.  (In the order listed in the
+     standard.)  */
+  REG_BADPAT,		/* Invalid pattern.  */
+  REG_ECOLLATE,		/* Not implemented.  */
+  REG_ECTYPE,		/* Invalid character class name.  */
+  REG_EESCAPE,		/* Trailing backslash.  */
+  REG_ESUBREG,		/* Invalid back reference.  */
+  REG_EBRACK,		/* Unmatched left bracket.  */
+  REG_EPAREN,		/* Parenthesis imbalance.  */ 
+  REG_EBRACE,		/* Unmatched \{.  */
+  REG_BADBR,		/* Invalid contents of \{\}.  */
+  REG_ERANGE,		/* Invalid range end.  */
+  REG_ESPACE,		/* Ran out of memory.  */
+  REG_BADRPT,		/* No preceding re for repetition op.  */
+
+  /* Error codes we've added.  */
+  REG_EEND,		/* Premature end.  */
+  REG_ESIZE,		/* Compiled pattern bigger than 2^16 bytes.  */
+  REG_ERPAREN		/* Unmatched ) or \); not returned from regcomp.  */
+} reg_errcode_t;
+
+/* This data structure represents a compiled pattern.  Before calling
+   the pattern compiler, the fields `buffer', `allocated', `fastmap',
+   `translate', and `no_sub' can be set.  After the pattern has been
+   compiled, the `re_nsub' field is available.  All other fields are
+   private to the regex routines.  */
+
+struct re_pattern_buffer
+{
+/* [[[begin pattern_buffer]]] */
+	/* Space that holds the compiled pattern.  It is declared as
+          `unsigned char *' because its elements are
+           sometimes used as array indexes.  */
+  unsigned char *buffer;
+
+	/* Number of bytes to which `buffer' points.  */
+  unsigned long allocated;
+
+	/* Number of bytes actually used in `buffer'.  */
+  unsigned long used;	
+
+        /* Syntax setting with which the pattern was compiled.  */
+  reg_syntax_t syntax;
+
+        /* Pointer to a fastmap, if any, otherwise zero.  re_search uses
+           the fastmap, if there is one, to skip over impossible
+           starting points for matches.  */
+  char *fastmap;
+
+        /* Either a translate table to apply to all characters before
+           comparing them, or zero for no translation.  The translation
+           is applied to a pattern when it is compiled and to a string
+           when it is matched.  */
+  char *translate;
+
+	/* Number of subexpressions found by the compiler.  */
+  size_t re_nsub;
+
+        /* Zero if this pattern cannot match the empty string, one else.
+           Well, in truth it's used only in `re_search_2', to see
+           whether or not we should use the fastmap, so we don't set
+           this absolutely perfectly; see `re_compile_fastmap' (the
+           `duplicate' case).  */
+  unsigned can_be_null : 1;
+
+        /* If REGS_UNALLOCATED, allocate space in the `regs' structure
+             for `max (RE_NREGS, re_nsub + 1)' groups.
+           If REGS_REALLOCATE, reallocate space if necessary.
+           If REGS_FIXED, use what's there.  */
+#define REGS_UNALLOCATED 0
+#define REGS_REALLOCATE 1
+#define REGS_FIXED 2
+  unsigned regs_allocated : 2;
+
+        /* Set to zero when `regex_compile' compiles a pattern; set to one
+           by `re_compile_fastmap' if it updates the fastmap.  */
+  unsigned fastmap_accurate : 1;
+
+        /* If set, `re_match_2' does not return information about
+           subexpressions.  */
+  unsigned no_sub : 1;
+
+        /* If set, a beginning-of-line anchor doesn't match at the
+           beginning of the string.  */ 
+  unsigned not_bol : 1;
+
+        /* Similarly for an end-of-line anchor.  */
+  unsigned not_eol : 1;
+
+        /* If true, an anchor at a newline matches.  */
+  unsigned newline_anchor : 1;
+
+/* [[[end pattern_buffer]]] */
+};
+
+typedef struct re_pattern_buffer regex_t;
+
+
+/* search.c (search_buffer) in Emacs needs this one opcode value.  It is
+   defined both in `regex.c' and here.  */
+#define RE_EXACTN_VALUE 1
+
+/* Type for byte offsets within the string.  POSIX mandates this.  */
+typedef int regoff_t;
+
+
+/* This is the structure we store register match data in.  See
+   regex.texinfo for a full description of what registers match.  */
+struct re_registers
+{
+  unsigned num_regs;
+  regoff_t *start;
+  regoff_t *end;
+};
+
+
+/* If `regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
+   `re_match_2' returns information about at least this many registers
+   the first time a `regs' structure is passed.  */
+#ifndef RE_NREGS
+#define RE_NREGS 30
+#endif
+
+
+/* POSIX specification for registers.  Aside from the different names than
+   `re_registers', POSIX uses an array of structures, instead of a
+   structure of arrays.  */
+typedef struct
+{
+  regoff_t rm_so;  /* Byte offset from string's start to substring's start.  */
+  regoff_t rm_eo;  /* Byte offset from string's start to substring's end.  */
+} regmatch_t;
+
+/* Declarations for routines.  */
+
+/* To avoid duplicating every routine declaration -- once with a
+   prototype (if we are ANSI), and once without (if we aren't) -- we
+   use the following macro to declare argument types.  This
+   unfortunately clutters up the declarations a bit, but I think it's
+   worth it.  */
+
+#if __STDC__
+
+#define _RE_ARGS(args) args
+
+#else /* not __STDC__ */
+
+#define _RE_ARGS(args) ()
+
+#endif /* not __STDC__ */
+
+/* Sets the current default syntax to SYNTAX, and return the old syntax.
+   You can also simply assign to the `re_syntax_options' variable.  */
+extern reg_syntax_t re_set_syntax _RE_ARGS ((reg_syntax_t syntax));
+
+/* Compile the regular expression PATTERN, with length LENGTH
+   and syntax given by the global `re_syntax_options', into the buffer
+   BUFFER.  Return NULL if successful, and an error string if not.  */
+extern const char *re_compile_pattern
+  _RE_ARGS ((const char *pattern, int length,
+             struct re_pattern_buffer *buffer));
+
+
+/* Compile a fastmap for the compiled pattern in BUFFER; used to
+   accelerate searches.  Return 0 if successful and -2 if was an
+   internal error.  */
+extern int re_compile_fastmap _RE_ARGS ((struct re_pattern_buffer *buffer));
+
+
+/* Search in the string STRING (with length LENGTH) for the pattern
+   compiled into BUFFER.  Start searching at position START, for RANGE
+   characters.  Return the starting position of the match, -1 for no
+   match, or -2 for an internal error.  Also return register
+   information in REGS (if REGS and BUFFER->no_sub are nonzero).  */
+extern int re_search
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string,
+            int length, int start, int range, struct re_registers *regs));
+
+
+/* Like `re_search', but search in the concatenation of STRING1 and
+   STRING2.  Also, stop searching at index START + STOP.  */
+extern int re_search_2
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string1,
+             int length1, const char *string2, int length2,
+             int start, int range, struct re_registers *regs, int stop));
+
+
+/* Like `re_search', but return how many characters in STRING the regexp
+   in BUFFER matched, starting at position START.  */
+extern int re_match
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string,
+             int length, int start, struct re_registers *regs));
+
+
+/* Relates to `re_match' as `re_search_2' relates to `re_search'.  */
+extern int re_match_2 
+  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string1,
+             int length1, const char *string2, int length2,
+             int start, struct re_registers *regs, int stop));
+
+
+/* Set REGS to hold NUM_REGS registers, storing them in STARTS and
+   ENDS.  Subsequent matches using BUFFER and REGS will use this memory
+   for recording register information.  STARTS and ENDS must be
+   allocated with malloc, and must each be at least `NUM_REGS * sizeof
+   (regoff_t)' bytes long.
+
+   If NUM_REGS == 0, then subsequent matches should allocate their own
+   register data.
+
+   Unless this function is called, the first search or match using
+   PATTERN_BUFFER will allocate its own register data, without
+   freeing the old data.  */
+extern void re_set_registers
+  _RE_ARGS ((struct re_pattern_buffer *buffer, struct re_registers *regs,
+             unsigned num_regs, regoff_t *starts, regoff_t *ends));
+
+/* 4.2 bsd compatibility.  */
+extern char *re_comp _RE_ARGS ((const char *));
+extern int re_exec _RE_ARGS ((const char *));
+
+/* POSIX compatibility.  */
+extern int regcomp _RE_ARGS ((regex_t *preg, const char *pattern, int cflags));
+extern int regexec
+  _RE_ARGS ((const regex_t *preg, const char *string, size_t nmatch,
+             regmatch_t pmatch[], int eflags));
+extern size_t regerror
+  _RE_ARGS ((int errcode, const regex_t *preg, char *errbuf,
+             size_t errbuf_size));
+extern void regfree _RE_ARGS ((regex_t *preg));
+
+#endif /* not __REGEXP_LIBRARY_H__ */
+
+/*
+Local variables:
+make-backup-files: t
+version-control: t
+trim-versions-without-asking: nil
+End:
+*/
diff --git a/gnu/usr.bin/diff/sdiff.1 b/gnu/usr.bin/diff/sdiff.1
new file mode 100644
index 00000000000..8b7e88c1314
--- /dev/null
+++ b/gnu/usr.bin/diff/sdiff.1
@@ -0,0 +1,198 @@
+.TH SDIFF 1 "22sep1993" "GNU Tools" "GNU Tools"
+.SH NAME
+sdiff \- find differences between two files and merge interactively
+.SH SYNOPSIS
+.B sdiff
+.B -o
+outfile [options] from-file to-file
+.SH DESCRIPTION
+The
+.I sdiff
+command merges two files and interactively outputs the
+results to
+.IR outfile .
+
+If
+.I from-file
+is a directory and
+.I to-file
+is not,
+.I sdiff
+compares the file in
+.I from-file
+whose file name is that of
+.IR to-file ,
+and vice versa.
+.I from-file
+and
+.I to-file
+may not both be
+directories.
+
+.I sdiff
+options begin with
+.BR \- ,
+so normally
+.I from-file
+and
+.I to-file
+may not begin with
+.BR \- .
+However,
+.B \-\-
+as an
+argument by itself treats the remaining arguments as file names even if
+they begin with
+.BR \- .
+You may not use
+.B \-
+as an input file.
+
+.I sdiff
+without
+.B \-o
+(or
+.BR \-\-output )
+produces a
+side-by-side difference.  This usage is obsolete; use
+.B "diff \-\-side\-by\-side"
+instead.
+.SS Options
+Below is a summary of all of the options that GNU
+.I sdiff
+accepts.
+Each option has two equivalent names, one of which is a single
+letter preceded by
+.BR \- ,
+and the other of which is a long name
+preceded by
+.BR \-\- .
+Multiple single letter options (unless they take
+an argument) can be combined into a single command line argument.  Long
+named options can be abbreviated to any unique prefix of their name.
+.TP
+.B \-a
+Treat all files as text and compare them line-by-line, even if they
+do not appear to be text.
+.TP
+.B \-b
+Ignore changes in amount of white space.
+.TP
+.B \-B
+Ignore changes that just insert or delete blank lines.
+.TP
+.B \-d
+Change the algorithm to perhaps find a smaller set of changes.  This
+makes
+.I sdiff
+slower (sometimes much slower).
+.TP
+.B \-H
+Use heuristics to speed handling of large files that have numerous
+scattered small changes.
+.TP
+.B \-\-expand\-tabs
+Expand tabs to spaces in the output, to preserve the alignment of tabs
+in the input files.
+.TP
+.B \-i
+Ignore changes in case; consider upper- and lower-case to be the same.
+.TP
+.BI "\-I " regexp
+Ignore changes that just insert or delete lines that match
+.IR regexp .
+.TP
+.B \-\-ignore\-all\-space
+Ignore white space when comparing lines.
+.TP
+.B \-\-ignore\-blank\-lines
+Ignore changes that just insert or delete blank lines.
+.TP
+.B \-\-ignore\-case
+Ignore changes in case; consider upper- and lower-case to be the same.
+.TP
+.BI \-\-ignore\-matching\-lines= regexp
+Ignore changes that just insert or delete lines that match
+.IR regexp .
+.TP
+.B \-\-ignore\-space\-change
+Ignore changes in amount of white space.
+.TP
+.B \-l
+.br
+.ns
+.TP
+.B \-\-left\-column
+Print only the left column of two common lines.
+.TP
+.B \-\-minimal
+Change the algorithm to perhaps find a smaller set of changes.  This
+makes
+.I sdiff
+slower (sometimes much slower).
+.TP
+.BI "\-o " file
+.br
+.ns
+.TP
+.BI \-\-output= file
+Put merged output into
+.IR file .
+This option is required for merging.
+.TP
+.B \-s
+.br
+.ns
+.TP
+.B \-\-suppress\-common\-lines
+Do not print common lines.
+.TP
+.B \-\-speed\-large\-files
+Use heuristics to speed handling of large files that have numerous
+scattered small changes.
+.TP
+.B \-t
+Expand tabs to spaces in the output, to preserve the alignment of tabs
+in the input files.
+.TP
+.B \-\-text
+Treat all files as text and compare them line-by-line, even if they
+do not appear to be text.
+.TP
+.B \-v
+.br
+.ns
+.TP
+.B \-\-version
+Output the version number of
+.IR sdiff .
+.TP
+.BI "\-w " columns
+.br
+.ns
+.TP
+.BI \-\-width= columns
+Use an output width of
+.IR columns .
+Note that for historical reasons, this option is
+.B \-W
+in
+.IR diff ,
+.B \-w
+in
+.IR sdiff .
+.TP
+.B \-W
+Ignore horizontal white space when comparing lines.
+Note that for historical reasons, this option is
+.B \-w
+in
+.IR diff ,
+.B \-W
+in
+.IR sdiff .
+.SH SEE ALSO
+cmp(1), comm(1), diff(1), diff3(1).
+.SH DIAGNOSTICS
+An exit status of 0 means no differences were found, 1 means some
+differences were found, and 2 means trouble.
diff --git a/gnu/usr.bin/diff/sdiff.c b/gnu/usr.bin/diff/sdiff.c
new file mode 100644
index 00000000000..b64f1d03836
--- /dev/null
+++ b/gnu/usr.bin/diff/sdiff.c
@@ -0,0 +1,1180 @@
+/* SDIFF -- interactive merge front end to diff
+   Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* GNU SDIFF was written by Thomas Lord. */
+
+#include "system.h"
+#include <stdio.h>
+#include <signal.h>
+#include "getopt.h"
+
+/* Size of chunks read from files which must be parsed into lines. */
+#define SDIFF_BUFSIZE ((size_t) 65536)
+
+/* Default name of the diff program */
+#ifndef DIFF_PROGRAM
+#define DIFF_PROGRAM "/usr/bin/diff"
+#endif
+
+/* Users' editor of nonchoice */
+#ifndef DEFAULT_EDITOR_PROGRAM
+#define DEFAULT_EDITOR_PROGRAM "ed"
+#endif
+
+extern char version_string[];
+static char const *program_name;
+static char const *diffbin = DIFF_PROGRAM;
+static char const *edbin = DEFAULT_EDITOR_PROGRAM;
+static char const **diffargv;
+
+static char *tmpname;
+static int volatile tmpmade;
+
+#if HAVE_FORK
+static pid_t volatile diffpid;
+#endif
+
+struct line_filter;
+
+static FILE *ck_fopen PARAMS((char const *, char const *));
+static RETSIGTYPE catchsig PARAMS((int));
+static VOID *xmalloc PARAMS((size_t));
+static char const *expand_name PARAMS((char *, int, char const *));
+static int edit PARAMS((struct line_filter *, int, struct line_filter *, int, FILE*));
+static int interact PARAMS((struct line_filter *, struct line_filter *, struct line_filter *, FILE*));
+static int lf_snarf PARAMS((struct line_filter *, char *, size_t));
+static int skip_white PARAMS((void));
+static size_t ck_fread PARAMS((char *, size_t, FILE *));
+static size_t lf_refill PARAMS((struct line_filter *));
+static void checksigs PARAMS((void));
+static void ck_fclose PARAMS((FILE *));
+static void ck_fflush PARAMS((FILE *));
+static void ck_fwrite PARAMS((char const *, size_t, FILE *));
+static void cleanup PARAMS((void));
+static void diffarg PARAMS((char const *));
+static void execdiff PARAMS((void));
+static void exiterr PARAMS((void));
+static void fatal PARAMS((char const *));
+static void flush_line PARAMS((void));
+static void give_help PARAMS((void));
+static void lf_copy PARAMS((struct line_filter *, int, FILE *));
+static void lf_init PARAMS((struct line_filter *, FILE *));
+static void lf_skip PARAMS((struct line_filter *, int));
+static void perror_fatal PARAMS((char const *));
+static void trapsigs PARAMS((void));
+static void try_help PARAMS((char const *));
+static void untrapsig PARAMS((int));
+static void usage PARAMS((void));
+
+/* this lossage until the gnu libc conquers the universe */
+#if HAVE_TMPNAM
+#define private_tempnam() tmpnam ((char *) 0)
+#else
+#ifndef PVT_tmpdir
+#define PVT_tmpdir "/tmp"
+#endif
+#ifndef TMPDIR_ENV
+#define TMPDIR_ENV "TMPDIR"
+#endif
+static char *private_tempnam PARAMS((void));
+static int exists PARAMS((char const *));
+#endif
+static int diraccess PARAMS((char const *));
+
+/* Options: */
+
+/* name of output file if -o spec'd */
+static char *out_file;
+
+/* do not print common lines if true, set by -s option */
+static int suppress_common_flag;
+
+static struct option const longopts[] =
+{
+  {"ignore-blank-lines", 0, 0, 'B'},
+  {"speed-large-files", 0, 0, 'H'},
+  {"ignore-matching-lines", 1, 0, 'I'},
+  {"ignore-all-space", 0, 0, 'W'}, /* swap W and w for historical reasons */
+  {"text", 0, 0, 'a'},
+  {"ignore-space-change", 0, 0, 'b'},
+  {"minimal", 0, 0, 'd'},
+  {"ignore-case", 0, 0, 'i'},
+  {"left-column", 0, 0, 'l'},
+  {"output", 1, 0, 'o'},
+  {"suppress-common-lines", 0, 0, 's'},
+  {"expand-tabs", 0, 0, 't'},
+  {"width", 1, 0, 'w'},
+  {"version", 0, 0, 'v'},
+  {"help", 0, 0, 129},
+  {0, 0, 0, 0}
+};
+
+static void
+try_help (reason)
+     char const *reason;
+{
+  if (reason)
+    fprintf (stderr, "%s: %s\n", program_name, reason);
+  fprintf (stderr, "%s: Try `%s --help' for more information.\n",
+	   program_name, program_name);
+  exit (2);
+}
+
+static void
+usage ()
+{
+  printf ("Usage: %s [OPTIONS]... FILE1 FILE2\n\n", program_name);
+  printf ("%s", "\
+  -o FILE  --output=FILE  Operate interactively, sending output to FILE.\n\n");
+  printf ("%s", "\
+  -i  --ignore-case  Consider upper- and lower-case to be the same.\n\
+  -W  --ignore-all-space  Ignore all white space.\n\
+  -b  --ignore-space-change  Ignore changes in the amount of white space.\n\
+  -B  --ignore-blank-lines  Ignore changes whose lines are all blank.\n\
+  -I RE  --ignore-matching-lines=RE  Ignore changes whose lines all match RE.\n\
+  -a  --text  Treat all files as text.\n\n");
+  printf ("%s", "\
+  -w NUM  --width=NUM  Output at most NUM (default 130) characters per line.\n\
+  -l  --left-column  Output only the left column of common lines.\n\
+  -s  --suppress-common-lines  Do not output common lines.\n\n");
+  printf ("\
+  -t  --expand-tabs  Expand tabs to spaces in output.\n\n");
+  printf ("%s", "\
+  -d  --minimal  Try hard to find a smaller set of changes.\n\
+  -H  --speed-large-files  Assume large files and many scattered small changes.\n\n");
+ printf ("%s", "\
+  -v  --version  Output version info.\n\
+  --help  Output this help.\n\n\
+If FILE1 or FILE2 is `-', read standard input.\n");
+}
+
+static void
+cleanup ()
+{
+#if HAVE_FORK
+  if (0 < diffpid)
+    kill (diffpid, SIGPIPE);
+#endif
+  if (tmpmade)
+    unlink (tmpname);
+}
+
+static void
+exiterr ()
+{
+  cleanup ();
+  untrapsig (0);
+  checksigs ();
+  exit (2);
+}
+
+static void
+fatal (msg)
+     char const *msg;
+{
+  fprintf (stderr, "%s: %s\n", program_name, msg);
+  exiterr ();
+}
+
+static void
+perror_fatal (msg)
+     char const *msg;
+{
+  int e = errno;
+  checksigs ();
+  fprintf (stderr, "%s: ", program_name);
+  errno = e;
+  perror (msg);
+  exiterr ();
+}
+
+
+/* malloc freely or DIE! */
+static VOID *
+xmalloc (size)
+     size_t size;
+{
+  VOID *r = (VOID *) malloc (size);
+  if (!r)
+    fatal ("memory exhausted");
+  return r;
+}
+
+static FILE *
+ck_fopen (fname, type)
+     char const *fname, *type;
+{
+  FILE *r = fopen (fname, type);
+  if (!r)
+    perror_fatal (fname);
+  return r;
+}
+
+static void
+ck_fclose (f)
+     FILE *f;
+{
+  if (fclose (f))
+    perror_fatal ("input/output error");
+}
+
+static size_t
+ck_fread (buf, size, f)
+     char *buf;
+     size_t size;
+     FILE *f;
+{
+  size_t r = fread (buf, sizeof (char), size, f);
+  if (r == 0 && ferror (f))
+    perror_fatal ("input error");
+  return r;
+}
+
+static void
+ck_fwrite (buf, size, f)
+     char const *buf;
+     size_t size;
+     FILE *f;
+{
+  if (fwrite (buf, sizeof (char), size, f) != size)
+    perror_fatal ("output error");
+}
+
+static void
+ck_fflush (f)
+     FILE *f;
+{
+  if (fflush (f) != 0)
+    perror_fatal ("output error");
+}
+
+static char const *
+expand_name (name, is_dir, other_name)
+     char *name;
+     int is_dir;
+     char const *other_name;
+{
+  if (strcmp (name, "-") == 0)
+    fatal ("cannot interactively merge standard input");
+  if (!is_dir)
+    return name;
+  else
+    {
+      /* Yield NAME/BASE, where BASE is OTHER_NAME's basename.  */
+      char const *p = filename_lastdirchar (other_name);
+      char const *base = p ? p+1 : other_name;
+      size_t namelen = strlen (name), baselen = strlen (base);
+      char *r = xmalloc (namelen + baselen + 2);
+      memcpy (r, name, namelen);
+      r[namelen] = '/';
+      memcpy (r + namelen + 1, base, baselen + 1);
+      return r;
+    }
+}
+
+
+
+struct line_filter {
+  FILE *infile;
+  char *bufpos;
+  char *buffer;
+  char *buflim;
+};
+
+static void
+lf_init (lf, infile)
+     struct line_filter *lf;
+     FILE *infile;
+{
+  lf->infile = infile;
+  lf->bufpos = lf->buffer = lf->buflim = xmalloc (SDIFF_BUFSIZE + 1);
+  lf->buflim[0] = '\n';
+}
+
+/* Fill an exhausted line_filter buffer from its INFILE */
+static size_t
+lf_refill (lf)
+     struct line_filter *lf;
+{
+  size_t s = ck_fread (lf->buffer, SDIFF_BUFSIZE, lf->infile);
+  lf->bufpos = lf->buffer;
+  lf->buflim = lf->buffer + s;
+  lf->buflim[0] = '\n';
+  checksigs ();
+  return s;
+}
+
+/* Advance LINES on LF's infile, copying lines to OUTFILE */
+static void
+lf_copy (lf, lines, outfile)
+     struct line_filter *lf;
+     int lines;
+     FILE *outfile;
+{
+  char *start = lf->bufpos;
+
+  while (lines)
+    {
+      lf->bufpos = (char *) memchr (lf->bufpos, '\n', lf->buflim - lf->bufpos);
+      if (! lf->bufpos)
+	{
+	  ck_fwrite (start, lf->buflim - start, outfile);
+	  if (! lf_refill (lf))
+	    return;
+	  start = lf->bufpos;
+	}
+      else
+	{
+	  --lines;
+	  ++lf->bufpos;
+	}
+    }
+
+  ck_fwrite (start, lf->bufpos - start, outfile);
+}
+
+/* Advance LINES on LF's infile without doing output */
+static void
+lf_skip (lf, lines)
+     struct line_filter *lf;
+     int lines;
+{
+  while (lines)
+    {
+      lf->bufpos = (char *) memchr (lf->bufpos, '\n', lf->buflim - lf->bufpos);
+      if (! lf->bufpos)
+	{
+	  if (! lf_refill (lf))
+	    break;
+	}
+      else
+	{
+	  --lines;
+	  ++lf->bufpos;
+	}
+    }
+}
+
+/* Snarf a line into a buffer.  Return EOF if EOF, 0 if error, 1 if OK.  */
+static int
+lf_snarf (lf, buffer, bufsize)
+     struct line_filter *lf;
+     char *buffer;
+     size_t bufsize;
+{
+  char *start = lf->bufpos;
+
+  for (;;)
+    {
+      char *next = (char *) memchr (start, '\n', lf->buflim + 1 - start);
+      size_t s = next - start;
+      if (bufsize <= s)
+	return 0;
+      memcpy (buffer, start, s);
+      if (next < lf->buflim)
+	{
+	  buffer[s] = 0;
+	  lf->bufpos = next + 1;
+	  return 1;
+	}
+      if (! lf_refill (lf))
+	return s ? 0 : EOF;
+      buffer += s;
+      bufsize -= s;
+      start = next;
+    }
+}
+
+
+
+int
+main (argc, argv)
+     int argc;
+     char *argv[];
+{
+  int opt;
+  char *editor;
+  char *differ;
+
+  initialize_main (&argc, &argv);
+  program_name = argv[0];
+
+  editor = getenv ("EDITOR");
+  if (editor)
+    edbin = editor;
+  differ = getenv ("DIFF");
+  if (differ)
+    diffbin = differ;
+
+  diffarg ("diff");
+
+  /* parse command line args */
+  while ((opt = getopt_long (argc, argv, "abBdHiI:lo:stvw:W", longopts, 0))
+	 != EOF)
+    {
+      switch (opt)
+	{
+	case 'a':
+	  diffarg ("-a");
+	  break;
+
+	case 'b':
+	  diffarg ("-b");
+	  break;
+
+	case 'B':
+	  diffarg ("-B");
+	  break;
+
+	case 'd':
+	  diffarg ("-d");
+	  break;
+
+	case 'H':
+	  diffarg ("-H");
+	  break;
+
+	case 'i':
+	  diffarg ("-i");
+	  break;
+
+	case 'I':
+	  diffarg ("-I");
+	  diffarg (optarg);
+	  break;
+
+	case 'l':
+	  diffarg ("--left-column");
+	  break;
+
+	case 'o':
+	  out_file = optarg;
+	  break;
+
+	case 's':
+	  suppress_common_flag = 1;
+	  break;
+
+	case 't':
+	  diffarg ("-t");
+	  break;
+
+	case 'v':
+	  printf ("sdiff - GNU diffutils version %s\n", version_string);
+	  exit (0);
+
+	case 'w':
+	  diffarg ("-W");
+	  diffarg (optarg);
+	  break;
+
+	case 'W':
+	  diffarg ("-w");
+	  break;
+
+	case 129:
+	  usage ();
+	  if (ferror (stdout) || fclose (stdout) != 0)
+	    fatal ("write error");
+	  exit (0);
+
+	default:
+	  try_help (0);
+	}
+    }
+
+  if (argc - optind != 2)
+    try_help (argc - optind < 2 ? "missing operand" : "extra operand");
+
+  if (! out_file)
+    {
+      /* easy case: diff does everything for us */
+      if (suppress_common_flag)
+	diffarg ("--suppress-common-lines");
+      diffarg ("-y");
+      diffarg ("--");
+      diffarg (argv[optind]);
+      diffarg (argv[optind + 1]);
+      diffarg (0);
+      execdiff ();
+    }
+  else
+    {
+      FILE *left, *right, *out, *diffout;
+      int interact_ok;
+      struct line_filter lfilt;
+      struct line_filter rfilt;
+      struct line_filter diff_filt;
+      int leftdir = diraccess (argv[optind]);
+      int rightdir = diraccess (argv[optind + 1]);
+
+      if (leftdir && rightdir)
+	fatal ("both files to be compared are directories");
+
+      left = ck_fopen (expand_name (argv[optind], leftdir, argv[optind + 1]), "r");
+      ;
+      right = ck_fopen (expand_name (argv[optind + 1], rightdir, argv[optind]), "r");
+      out = ck_fopen (out_file, "w");
+
+      diffarg ("--sdiff-merge-assist");
+      diffarg ("--");
+      diffarg (argv[optind]);
+      diffarg (argv[optind + 1]);
+      diffarg (0);
+
+      trapsigs ();
+
+#if ! HAVE_FORK
+      {
+	size_t cmdsize = 1;
+	char *p, *command;
+	int i;
+
+	for (i = 0;  diffargv[i];  i++)
+	  cmdsize += 4 * strlen (diffargv[i]) + 3;
+	command = p = xmalloc (cmdsize);
+	for (i = 0;  diffargv[i];  i++)
+	  {
+	    char const *a = diffargv[i];
+	    SYSTEM_QUOTE_ARG (p, a);
+	    *p++ = ' ';
+	  }
+	p[-1] = '\0';
+	diffout = popen (command, "r");
+	if (!diffout)
+	  perror_fatal (command);
+	free (command);
+      }
+#else /* HAVE_FORK */
+      {
+	int diff_fds[2];
+
+	if (pipe (diff_fds) != 0)
+	  perror_fatal ("pipe");
+
+	diffpid = vfork ();
+	if (diffpid < 0)
+	  perror_fatal ("fork failed");
+	if (!diffpid)
+	  {
+	    signal (SIGINT, SIG_IGN);  /* in case user interrupts editor */
+	    signal (SIGPIPE, SIG_DFL);
+
+	    close (diff_fds[0]);
+	    if (diff_fds[1] != STDOUT_FILENO)
+	      {
+		dup2 (diff_fds[1], STDOUT_FILENO);
+		close (diff_fds[1]);
+	      }
+
+	    execdiff ();
+	  }
+
+	close (diff_fds[1]);
+	diffout = fdopen (diff_fds[0], "r");
+	if (!diffout)
+	  perror_fatal ("fdopen");
+      }
+#endif /* HAVE_FORK */
+
+      lf_init (&diff_filt, diffout);
+      lf_init (&lfilt, left);
+      lf_init (&rfilt, right);
+
+      interact_ok = interact (&diff_filt, &lfilt, &rfilt, out);
+
+      ck_fclose (left);
+      ck_fclose (right);
+      ck_fclose (out);
+
+      {
+	int wstatus;
+
+#if ! HAVE_FORK
+	wstatus = pclose (diffout);
+#else
+	ck_fclose (diffout);
+	while (waitpid (diffpid, &wstatus, 0) < 0)
+	  if (errno == EINTR)
+	    checksigs ();
+	  else
+	    perror_fatal ("wait failed");
+	diffpid = 0;
+#endif
+
+	if (tmpmade)
+	  {
+	    unlink (tmpname);
+	    tmpmade = 0;
+	  }
+
+	if (! interact_ok)
+	  exiterr ();
+
+	if (! (WIFEXITED (wstatus) && WEXITSTATUS (wstatus) < 2))
+	  fatal ("Subsidiary diff failed");
+
+	untrapsig (0);
+	checksigs ();
+	exit (WEXITSTATUS (wstatus));
+      }
+    }
+  return 0;			/* Fool -Wall . . . */
+}
+
+static void
+diffarg (a)
+     char const *a;
+{
+  static unsigned diffargs, diffargsmax;
+
+  if (diffargs == diffargsmax)
+    {
+      if (! diffargsmax)
+	{
+	  diffargv = (char const **) xmalloc (sizeof (char));
+	  diffargsmax = 8;
+	}
+      diffargsmax *= 2;
+      diffargv = (char const **) realloc (diffargv,
+					  diffargsmax * sizeof (char const *));
+      if (! diffargv)
+	fatal ("out of memory");
+    }
+  diffargv[diffargs++] = a;
+}
+
+static void
+execdiff ()
+{
+  execvp (diffbin, (char **) diffargv);
+  write (STDERR_FILENO, diffbin, strlen (diffbin));
+  write (STDERR_FILENO, ": not found\n", 12);
+  _exit (2);
+}
+
+
+
+
+/* Signal handling */
+
+#define NUM_SIGS (sizeof (sigs) / sizeof (*sigs))
+static int const sigs[] = {
+#ifdef SIGHUP
+       SIGHUP,
+#endif
+#ifdef SIGQUIT
+       SIGQUIT,
+#endif
+#ifdef SIGTERM
+       SIGTERM,
+#endif
+#ifdef SIGXCPU
+       SIGXCPU,
+#endif
+#ifdef SIGXFSZ
+       SIGXFSZ,
+#endif
+       SIGINT,
+       SIGPIPE
+};
+
+/* Prefer `sigaction' if it is available, since `signal' can lose signals.  */
+#if HAVE_SIGACTION
+static struct sigaction initial_action[NUM_SIGS];
+#define initial_handler(i) (initial_action[i].sa_handler)
+#else
+static RETSIGTYPE (*initial_action[NUM_SIGS]) ();
+#define initial_handler(i) (initial_action[i])
+#endif
+
+static int volatile ignore_SIGINT;
+static int volatile signal_received;
+static int sigs_trapped;
+
+static RETSIGTYPE
+catchsig (s)
+     int s;
+{
+#if ! HAVE_SIGACTION
+  signal (s, SIG_IGN);
+#endif
+  if (! (s == SIGINT && ignore_SIGINT))
+    signal_received = s;
+}
+
+static void
+trapsigs ()
+{
+  int i;
+
+#if HAVE_SIGACTION
+  struct sigaction catchaction;
+  bzero (&catchaction, sizeof (catchaction));
+  catchaction.sa_handler = catchsig;
+#ifdef SA_INTERRUPT
+  /* Non-Posix BSD-style systems like SunOS 4.1.x need this
+     so that `read' calls are interrupted properly.  */
+  catchaction.sa_flags = SA_INTERRUPT;
+#endif
+  sigemptyset (&catchaction.sa_mask);
+  for (i = 0;  i < NUM_SIGS;  i++)
+    sigaddset (&catchaction.sa_mask, sigs[i]);
+  for (i = 0;  i < NUM_SIGS;  i++)
+    {
+      sigaction (sigs[i], 0, &initial_action[i]);
+      if (initial_handler (i) != SIG_IGN
+	  && sigaction (sigs[i], &catchaction, 0) != 0)
+	fatal ("signal error");
+    }
+#else /* ! HAVE_SIGACTION */
+  for (i = 0;  i < NUM_SIGS;  i++)
+    {
+      initial_action[i] = signal (sigs[i], SIG_IGN);
+      if (initial_handler (i) != SIG_IGN
+	  && signal (sigs[i], catchsig) != SIG_IGN)
+	fatal ("signal error");
+    }
+#endif /* ! HAVE_SIGACTION */
+
+#if !defined(SIGCHLD) && defined(SIGCLD)
+#define SIGCHLD SIGCLD
+#endif
+#ifdef SIGCHLD
+  /* System V fork+wait does not work if SIGCHLD is ignored.  */
+  signal (SIGCHLD, SIG_DFL);
+#endif
+
+  sigs_trapped = 1;
+}
+
+/* Untrap signal S, or all trapped signals if S is zero.  */
+static void
+untrapsig (s)
+     int s;
+{
+  int i;
+
+  if (sigs_trapped)
+    for (i = 0;  i < NUM_SIGS;  i++)
+      if ((!s || sigs[i] == s)  &&  initial_handler (i) != SIG_IGN)
+#if HAVE_SIGACTION
+	  sigaction (sigs[i], &initial_action[i], 0);
+#else
+	  signal (sigs[i], initial_action[i]);
+#endif
+}
+
+/* Exit if a signal has been received.  */
+static void
+checksigs ()
+{
+  int s = signal_received;
+  if (s)
+    {
+      cleanup ();
+
+      /* Yield an exit status indicating that a signal was received.  */
+      untrapsig (s);
+      kill (getpid (), s);
+
+      /* That didn't work, so exit with error status.  */
+      exit (2);
+    }
+}
+
+
+
+static void
+give_help ()
+{
+  fprintf (stderr,"l:\tuse the left version\n");
+  fprintf (stderr,"r:\tuse the right version\n");
+  fprintf (stderr,"e l:\tedit then use the left version\n");
+  fprintf (stderr,"e r:\tedit then use the right version\n");
+  fprintf (stderr,"e b:\tedit then use the left and right versions concatenated\n");
+  fprintf (stderr,"e:\tedit a new version\n");
+  fprintf (stderr,"s:\tsilently include common lines\n");
+  fprintf (stderr,"v:\tverbosely include common lines\n");
+  fprintf (stderr,"q:\tquit\n");
+}
+
+static int
+skip_white ()
+{
+  int c;
+  for (;;)
+    {
+      c = getchar ();
+      if (!ISSPACE (c) || c == '\n')
+	break;
+      checksigs ();
+    }
+  if (ferror (stdin))
+    perror_fatal ("input error");
+  return c;
+}
+
+static void
+flush_line ()
+{
+  int c;
+  while ((c = getchar ()) != '\n' && c != EOF)
+    ;
+  if (ferror (stdin))
+    perror_fatal ("input error");
+}
+
+
+/* interpret an edit command */
+static int
+edit (left, lenl, right, lenr, outfile)
+     struct line_filter *left;
+     int lenl;
+     struct line_filter *right;
+     int lenr;
+     FILE *outfile;
+{
+  for (;;)
+    {
+      int cmd0, cmd1;
+      int gotcmd = 0;
+
+      cmd1 = 0; /* Pacify `gcc -W'.  */
+
+      while (!gotcmd)
+	{
+	  if (putchar ('%') != '%')
+	    perror_fatal ("output error");
+	  ck_fflush (stdout);
+
+	  cmd0 = skip_white ();
+	  switch (cmd0)
+	    {
+	    case 'l': case 'r': case 's': case 'v': case 'q':
+	      if (skip_white () != '\n')
+		{
+		  give_help ();
+		  flush_line ();
+		  continue;
+		}
+	      gotcmd = 1;
+	      break;
+
+	    case 'e':
+	      cmd1 = skip_white ();
+	      switch (cmd1)
+		{
+		case 'l': case 'r': case 'b':
+		  if (skip_white () != '\n')
+		    {
+		      give_help ();
+		      flush_line ();
+		      continue;
+		    }
+		  gotcmd = 1;
+		  break;
+		case '\n':
+		  gotcmd = 1;
+		  break;
+		default:
+		  give_help ();
+		  flush_line ();
+		  continue;
+		}
+	      break;
+	    case EOF:
+	      if (feof (stdin))
+		{
+		  gotcmd = 1;
+		  cmd0 = 'q';
+		  break;
+		}
+	      /* falls through */
+	    default:
+	      flush_line ();
+	      /* falls through */
+	    case '\n':
+	      give_help ();
+	      continue;
+	    }
+	}
+
+      switch (cmd0)
+	{
+	case 'l':
+	  lf_copy (left, lenl, outfile);
+	  lf_skip (right, lenr);
+	  return 1;
+	case 'r':
+	  lf_copy (right, lenr, outfile);
+	  lf_skip (left, lenl);
+	  return 1;
+	case 's':
+	  suppress_common_flag = 1;
+	  break;
+	case 'v':
+	  suppress_common_flag = 0;
+	  break;
+	case 'q':
+	  return 0;
+	case 'e':
+	  if (! tmpname && ! (tmpname = private_tempnam ()))
+	    perror_fatal ("temporary file name");
+
+	  tmpmade = 1;
+
+	  {
+	    FILE *tmp = ck_fopen (tmpname, "w+");
+
+	    if (cmd1 == 'l' || cmd1 == 'b')
+	      lf_copy (left, lenl, tmp);
+	    else
+	      lf_skip (left, lenl);
+
+	    if (cmd1 == 'r' || cmd1 == 'b')
+	      lf_copy (right, lenr, tmp);
+	    else
+	      lf_skip (right, lenr);
+
+	    ck_fflush (tmp);
+
+	    {
+	      int wstatus;
+#if ! HAVE_FORK
+	      char *command = xmalloc (strlen (edbin) + strlen (tmpname) + 2);
+	      sprintf (command, "%s %s", edbin, tmpname);
+	      wstatus = system (command);
+	      free (command);
+#else /* HAVE_FORK */
+	      pid_t pid;
+
+	      ignore_SIGINT = 1;
+	      checksigs ();
+
+	      pid = vfork ();
+	      if (pid == 0)
+		{
+		  char const *argv[3];
+		  int i = 0;
+
+		  argv[i++] = edbin;
+		  argv[i++] = tmpname;
+		  argv[i++] = 0;
+
+		  execvp (edbin, (char **) argv);
+		  write (STDERR_FILENO, edbin, strlen (edbin));
+		  write (STDERR_FILENO, ": not found\n", 12);
+		  _exit (1);
+		}
+
+	      if (pid < 0)
+		perror_fatal ("fork failed");
+
+	      while (waitpid (pid, &wstatus, 0) < 0)
+		if (errno == EINTR)
+		  checksigs ();
+		else
+		  perror_fatal ("wait failed");
+
+	      ignore_SIGINT = 0;
+#endif /* HAVE_FORK */
+
+	      if (wstatus != 0)
+		fatal ("Subsidiary editor failed");
+	    }
+
+	    if (fseek (tmp, 0L, SEEK_SET) != 0)
+	      perror_fatal ("fseek");
+	    {
+	      /* SDIFF_BUFSIZE is too big for a local var
+		 in some compilers, so we allocate it dynamically.  */
+	      char *buf = xmalloc (SDIFF_BUFSIZE);
+	      size_t size;
+
+	      while ((size = ck_fread (buf, SDIFF_BUFSIZE, tmp)) != 0)
+		{
+		  checksigs ();
+		  ck_fwrite (buf, size, outfile);
+		}
+	      ck_fclose (tmp);
+
+	      free (buf);
+	    }
+	    return 1;
+	  }
+	default:
+	  give_help ();
+	  break;
+	}
+    }
+}
+
+
+
+/* Alternately reveal bursts of diff output and handle user commands.  */
+static int
+interact (diff, left, right, outfile)
+     struct line_filter *diff;
+     struct line_filter *left;
+     struct line_filter *right;
+     FILE *outfile;
+{
+  for (;;)
+    {
+      char diff_help[256];
+      int snarfed = lf_snarf (diff, diff_help, sizeof (diff_help));
+
+      if (snarfed <= 0)
+	return snarfed;
+
+      checksigs ();
+
+      switch (diff_help[0])
+	{
+	case ' ':
+	  puts (diff_help + 1);
+	  break;
+	case 'i':
+	  {
+	    int lenl = atoi (diff_help + 1), lenr, lenmax;
+	    char *p = strchr (diff_help, ',');
+
+	    if (!p)
+	      fatal (diff_help);
+	    lenr = atoi (p + 1);
+	    lenmax = max (lenl, lenr);
+
+	    if (suppress_common_flag)
+	      lf_skip (diff, lenmax);
+	    else
+	      lf_copy (diff, lenmax, stdout);
+
+	    lf_copy (left, lenl, outfile);
+	    lf_skip (right, lenr);
+	    break;
+	  }
+	case 'c':
+	  {
+	    int lenl = atoi (diff_help + 1), lenr;
+	    char *p = strchr (diff_help, ',');
+
+	    if (!p)
+	      fatal (diff_help);
+	    lenr = atoi (p + 1);
+	    lf_copy (diff, max (lenl, lenr), stdout);
+	    if (! edit (left, lenl, right, lenr, outfile))
+	      return 0;
+	    break;
+	  }
+	default:
+	  fatal (diff_help);
+	  break;
+	}
+    }
+}
+
+
+
+/* temporary lossage: this is torn from gnu libc */
+/* Return nonzero if DIR is an existing directory.  */
+static int
+diraccess (dir)
+     char const *dir;
+{
+  struct stat buf;
+  return stat (dir, &buf) == 0 && S_ISDIR (buf.st_mode);
+}
+
+#if ! HAVE_TMPNAM
+
+/* Return zero if we know that FILE does not exist.  */
+static int
+exists (file)
+     char const *file;
+{
+  struct stat buf;
+  return stat (file, &buf) == 0 || errno != ENOENT;
+}
+
+/* These are the characters used in temporary filenames.  */
+static char const letters[] =
+  "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+
+/* Generate a temporary filename and return it (in a newly allocated buffer).
+   Use the prefix "dif" as in tempnam.
+   This goes through a cyclic pattern of all possible
+   filenames consisting of five decimal digits of the current pid and three
+   of the characters in `letters'.  Each potential filename is
+   tested for an already-existing file of the same name, and no name of an
+   existing file will be returned.  When the cycle reaches its end
+   return 0.  */
+static char *
+private_tempnam ()
+{
+  char const *dir = getenv (TMPDIR_ENV);
+  static char const tmpdir[] = PVT_tmpdir;
+  size_t index;
+  char *buf;
+  pid_t pid = getpid ();
+  size_t dlen;
+
+  if (!dir)
+    dir = tmpdir;
+
+  dlen = strlen (dir);
+
+  /* Remove trailing slashes from the directory name.  */
+  while (dlen && dir[dlen - 1] == '/')
+    --dlen;
+
+  buf = xmalloc (dlen + 1 + 3 + 5 + 1 + 3 + 1);
+
+  sprintf (buf, "%.*s/.", (int) dlen, dir);
+  if (diraccess (buf))
+    {
+      for (index = 0;
+	   index < ((sizeof (letters) - 1) * (sizeof (letters) - 1)
+		    * (sizeof (letters) - 1));
+	   ++index)
+	{
+	  /* Construct a file name and see if it already exists.
+
+	     We use a single counter in INDEX to cycle each of three
+	     character positions through each of 62 possible letters.  */
+
+	  sprintf (buf, "%.*s/dif%.5lu.%c%c%c", (int) dlen, dir,
+		   (unsigned long) pid % 100000,
+		   letters[index % (sizeof (letters) - 1)],
+		   letters[(index / (sizeof (letters) - 1))
+			   % (sizeof (letters) - 1)],
+		   letters[index / ((sizeof (letters) - 1) *
+				     (sizeof (letters) - 1))]);
+
+	  if (!exists (buf))
+	    return buf;
+	}
+      errno = EEXIST;
+    }
+
+  /* Don't free buf; `free' might change errno.  We'll exit soon anyway.  */
+  return 0;
+}
+
+#endif /* ! HAVE_TMPNAM */
diff --git a/gnu/usr.bin/diff/side.c b/gnu/usr.bin/diff/side.c
new file mode 100644
index 00000000000..a150b5e705f
--- /dev/null
+++ b/gnu/usr.bin/diff/side.c
@@ -0,0 +1,284 @@
+/* sdiff-format output routines for GNU DIFF.
+   Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY.  No author or distributor
+accepts responsibility to anyone for the consequences of using it
+or for whether it serves any particular purpose or works at all,
+unless he says so in writing.  Refer to the GNU DIFF General Public
+License for full details.
+
+Everyone is granted permission to copy, modify and redistribute
+GNU DIFF, but only under the conditions described in the
+GNU DIFF General Public License.   A copy of this license is
+supposed to have been given to you along with GNU DIFF so you
+can know your rights and responsibilities.  It should be in a
+file named COPYING.  Among other things, the copyright notice
+and this notice must be preserved on all copies.  */
+
+
+#include "diff.h"
+
+static unsigned print_half_line PARAMS((char const * const *, unsigned, unsigned));
+static unsigned tab_from_to PARAMS((unsigned, unsigned));
+static void print_1sdiff_line PARAMS((char const * const *, int, char const * const *));
+static void print_sdiff_common_lines PARAMS((int, int));
+static void print_sdiff_hunk PARAMS((struct change *));
+
+/* Next line number to be printed in the two input files.  */
+static int next0, next1;
+
+/* Print the edit-script SCRIPT as a sdiff style output.  */
+
+void
+print_sdiff_script (script)
+     struct change *script;
+{
+  begin_output ();
+
+  next0 = next1 = - files[0].prefix_lines;
+  print_script (script, find_change, print_sdiff_hunk);
+
+  print_sdiff_common_lines (files[0].valid_lines, files[1].valid_lines);
+}
+
+/* Tab from column FROM to column TO, where FROM <= TO.  Yield TO.  */
+
+static unsigned
+tab_from_to (from, to)
+     unsigned from, to;
+{
+  FILE *out = outfile;
+  unsigned tab;
+
+  if (! tab_expand_flag)
+    for (tab = from + TAB_WIDTH - from % TAB_WIDTH;  tab <= to;  tab += TAB_WIDTH)
+      {
+	putc ('\t', out);
+	from = tab;
+      }
+  while (from++ < to)
+    putc (' ', out);
+  return to;
+}
+
+/*
+ * Print the text for half an sdiff line.  This means truncate to width
+ * observing tabs, and trim a trailing newline.  Returns the last column
+ * written (not the number of chars).
+ */
+static unsigned
+print_half_line (line, indent, out_bound)
+     char const * const *line;
+     unsigned indent, out_bound;
+{
+  FILE *out = outfile;
+  register unsigned in_position = 0, out_position = 0;
+  register char const
+	*text_pointer = line[0],
+	*text_limit = line[1];
+
+  while (text_pointer < text_limit)
+    {
+      register unsigned char c = *text_pointer++;
+
+      switch (c)
+	{
+	case '\t':
+	  {
+	    unsigned spaces = TAB_WIDTH - in_position % TAB_WIDTH;
+	    if (in_position == out_position)
+	      {
+		unsigned tabstop = out_position + spaces;
+		if (tab_expand_flag)
+		  {
+		    if (out_bound < tabstop)
+		      tabstop = out_bound;
+		    for (;  out_position < tabstop;  out_position++)
+		      putc (' ', out);
+		  }
+		else
+		  if (tabstop < out_bound)
+		    {
+		      out_position = tabstop;
+		      putc (c, out);
+		    }
+	      }
+	    in_position += spaces;
+	  }
+	  break;
+
+	case '\r':
+	  {
+	    putc (c, out);
+	    tab_from_to (0, indent);
+	    in_position = out_position = 0;
+	  }
+	  break;
+
+	case '\b':
+	  if (in_position != 0 && --in_position < out_bound)
+	    if (out_position <= in_position)
+	      /* Add spaces to make up for suppressed tab past out_bound.  */
+	      for (;  out_position < in_position;  out_position++)
+		putc (' ', out);
+	    else
+	      {
+		out_position = in_position;
+		putc (c, out);
+	      }
+	  break;
+
+	case '\f':
+	case '\v':
+	control_char:
+	  if (in_position < out_bound)
+	    putc (c, out);
+	  break;
+
+	default:
+	  if (! ISPRINT (c))
+	    goto control_char;
+	  /* falls through */
+	case ' ':
+	  if (in_position++ < out_bound)
+	    {
+	      out_position = in_position;
+	      putc (c, out);
+	    }
+	  break;
+
+	case '\n':
+	  return out_position;
+	}
+    }
+
+  return out_position;
+}
+
+/*
+ * Print side by side lines with a separator in the middle.
+ * 0 parameters are taken to indicate white space text.
+ * Blank lines that can easily be caught are reduced to a single newline.
+ */
+
+static void
+print_1sdiff_line (left, sep, right)
+     char const * const *left;
+     int sep;
+     char const * const *right;
+{
+  FILE *out = outfile;
+  unsigned hw = sdiff_half_width, c2o = sdiff_column2_offset;
+  unsigned col = 0;
+  int put_newline = 0;
+
+  if (left)
+    {
+      if (left[1][-1] == '\n')
+	put_newline = 1;
+      col = print_half_line (left, 0, hw);
+    }
+
+  if (sep != ' ')
+    {
+      col = tab_from_to (col, (hw + c2o - 1) / 2) + 1;
+      if (sep == '|' && put_newline != (right[1][-1] == '\n'))
+	sep = put_newline ? '/' : '\\';
+      putc (sep, out);
+    }
+
+  if (right)
+    {
+      if (right[1][-1] == '\n')
+	put_newline = 1;
+      if (**right != '\n')
+	{
+	  col = tab_from_to (col, c2o);
+	  print_half_line (right, col, hw);
+	}
+    }
+
+  if (put_newline)
+    putc ('\n', out);
+}
+
+/* Print lines common to both files in side-by-side format.  */
+static void
+print_sdiff_common_lines (limit0, limit1)
+     int limit0, limit1;
+{
+  int i0 = next0, i1 = next1;
+
+  if (! sdiff_skip_common_lines  &&  (i0 != limit0 || i1 != limit1))
+    {
+      if (sdiff_help_sdiff)
+	fprintf (outfile, "i%d,%d\n", limit0 - i0, limit1 - i1);
+
+      if (! sdiff_left_only)
+	{
+	  while (i0 != limit0 && i1 != limit1)
+	    print_1sdiff_line (&files[0].linbuf[i0++], ' ', &files[1].linbuf[i1++]);
+	  while (i1 != limit1)
+	    print_1sdiff_line (0, ')', &files[1].linbuf[i1++]);
+	}
+      while (i0 != limit0)
+	print_1sdiff_line (&files[0].linbuf[i0++], '(', 0);
+    }
+
+  next0 = limit0;
+  next1 = limit1;
+}
+
+/* Print a hunk of an sdiff diff.
+   This is a contiguous portion of a complete edit script,
+   describing changes in consecutive lines.  */
+
+static void
+print_sdiff_hunk (hunk)
+     struct change *hunk;
+{
+  int first0, last0, first1, last1, deletes, inserts;
+  register int i, j;
+
+  /* Determine range of line numbers involved in each file.  */
+  analyze_hunk (hunk, &first0, &last0, &first1, &last1, &deletes, &inserts);
+  if (!deletes && !inserts)
+    return;
+
+  /* Print out lines up to this change.  */
+  print_sdiff_common_lines (first0, first1);
+
+  if (sdiff_help_sdiff)
+    fprintf (outfile, "c%d,%d\n", last0 - first0 + 1, last1 - first1 + 1);
+
+  /* Print ``xxx  |  xxx '' lines */
+  if (inserts && deletes)
+    {
+      for (i = first0, j = first1;  i <= last0 && j <= last1; ++i, ++j)
+	print_1sdiff_line (&files[0].linbuf[i], '|', &files[1].linbuf[j]);
+      deletes = i <= last0;
+      inserts = j <= last1;
+      next0 = first0 = i;
+      next1 = first1 = j;
+    }
+
+
+  /* Print ``     >  xxx '' lines */
+  if (inserts)
+    {
+      for (j = first1; j <= last1; ++j)
+	print_1sdiff_line (0, '>', &files[1].linbuf[j]);
+      next1 = j;
+    }
+
+  /* Print ``xxx  <     '' lines */
+  if (deletes)
+    {
+      for (i = first0; i <= last0; ++i)
+	print_1sdiff_line (&files[0].linbuf[i], '<', 0);
+      next0 = i;
+    }
+}
diff --git a/gnu/usr.bin/diff/system.h b/gnu/usr.bin/diff/system.h
new file mode 100644
index 00000000000..d60af60005f
--- /dev/null
+++ b/gnu/usr.bin/diff/system.h
@@ -0,0 +1,267 @@
+/* System dependent declarations.
+   Copyright (C) 1988, 1989, 1992, 1993, 1994 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* We must define `volatile' and `const' first (the latter inside config.h),
+   so that they're used consistently in all system includes.  */
+#if !__STDC__
+#ifndef volatile
+#define volatile
+#endif
+#endif
+#include <config.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#if __STDC__
+#define PARAMS(args) args
+#define VOID void
+#else
+#define PARAMS(args) ()
+#define VOID char
+#endif
+
+#if STAT_MACROS_BROKEN
+#undef S_ISBLK
+#undef S_ISCHR
+#undef S_ISDIR
+#undef S_ISFIFO
+#undef S_ISREG
+#undef S_ISSOCK
+#endif
+#ifndef S_ISDIR
+#define S_ISDIR(mode) (((mode) & S_IFMT) == S_IFDIR)
+#endif
+#ifndef S_ISREG
+#define S_ISREG(mode) (((mode) & S_IFMT) == S_IFREG)
+#endif
+#if !defined(S_ISBLK) && defined(S_IFBLK)
+#define S_ISBLK(mode) (((mode) & S_IFMT) == S_IFBLK)
+#endif
+#if !defined(S_ISCHR) && defined(S_IFCHR)
+#define S_ISCHR(mode) (((mode) & S_IFMT) == S_IFCHR)
+#endif
+#if !defined(S_ISFIFO) && defined(S_IFFIFO)
+#define S_ISFIFO(mode) (((mode) & S_IFMT) == S_IFFIFO)
+#endif
+#if !defined(S_ISSOCK) && defined(S_IFSOCK)
+#define S_ISSOCK(mode) (((mode) & S_IFMT) == S_IFSOCK)
+#endif
+
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#ifndef SEEK_SET
+#define SEEK_SET 0
+#endif
+#ifndef SEEK_CUR
+#define SEEK_CUR 1
+#endif
+
+#ifndef STDIN_FILENO
+#define STDIN_FILENO 0
+#endif
+#ifndef STDOUT_FILENO
+#define STDOUT_FILENO 1
+#endif
+#ifndef STDERR_FILENO
+#define STDERR_FILENO 2
+#endif
+
+#if HAVE_TIME_H
+#include <time.h>
+#else
+#include <sys/time.h>
+#endif
+
+#if HAVE_FCNTL_H
+#include <fcntl.h>
+#else
+#if HAVE_SYS_FILE_H
+#include <sys/file.h>
+#endif
+#endif
+
+#if !HAVE_DUP2
+#define dup2(f,t)	(close (t),  fcntl (f,F_DUPFD,t))
+#endif
+
+#ifndef O_RDONLY
+#define O_RDONLY 0
+#endif
+
+#if HAVE_SYS_WAIT_H
+#include <sys/wait.h>
+#endif
+#ifndef WEXITSTATUS
+#define WEXITSTATUS(stat_val) ((unsigned) (stat_val) >> 8)
+#endif
+#ifndef WIFEXITED
+#define WIFEXITED(stat_val) (((stat_val) & 255) == 0)
+#endif
+
+#ifndef STAT_BLOCKSIZE
+#if HAVE_ST_BLKSIZE
+#define STAT_BLOCKSIZE(s) (s).st_blksize
+#else
+#define STAT_BLOCKSIZE(s) (8 * 1024)
+#endif
+#endif
+
+#if HAVE_DIRENT_H
+# include <dirent.h>
+# define NAMLEN(dirent) strlen((dirent)->d_name)
+#else
+# define dirent direct
+# define NAMLEN(dirent) ((dirent)->d_namlen)
+# if HAVE_SYS_NDIR_H
+#  include <sys/ndir.h>
+# endif
+# if HAVE_SYS_DIR_H
+#  include <sys/dir.h>
+# endif
+# if HAVE_NDIR_H
+#  include <ndir.h>
+# endif
+#endif
+
+#if HAVE_VFORK_H
+#include <vfork.h>
+#endif
+
+#if HAVE_STDLIB_H
+#include <stdlib.h>
+#else
+VOID *malloc ();
+VOID *realloc ();
+#endif
+#ifndef getenv
+char *getenv ();
+#endif
+
+#if HAVE_LIMITS_H
+#include <limits.h>
+#endif
+#ifndef INT_MAX
+#define INT_MAX 2147483647
+#endif
+#ifndef CHAR_BIT
+#define CHAR_BIT 8
+#endif
+
+#if STDC_HEADERS || HAVE_STRING_H
+# include <string.h>
+# ifndef bzero
+#  define bzero(s, n) memset (s, 0, n)
+# endif
+#else
+# if !HAVE_STRCHR
+#  define strchr index
+#  define strrchr rindex
+# endif
+char *strchr (), *strrchr ();
+# if !HAVE_MEMCHR
+#  define memcmp(s1, s2, n) bcmp (s1, s2, n)
+#  define memcpy(d, s, n) bcopy (s, d, n)
+void *memchr ();
+# endif
+#endif
+
+#include <ctype.h>
+/* CTYPE_DOMAIN (C) is nonzero if the unsigned char C can safely be given
+   as an argument to <ctype.h> macros like `isspace'.  */
+#if STDC_HEADERS
+#define CTYPE_DOMAIN(c) 1
+#else
+#define CTYPE_DOMAIN(c) ((unsigned) (c) <= 0177)
+#endif
+#ifndef ISPRINT
+#define ISPRINT(c) (CTYPE_DOMAIN (c) && isprint (c))
+#endif
+#ifndef ISSPACE
+#define ISSPACE(c) (CTYPE_DOMAIN (c) && isspace (c))
+#endif
+#ifndef ISUPPER
+#define ISUPPER(c) (CTYPE_DOMAIN (c) && isupper (c))
+#endif
+
+#ifndef ISDIGIT
+#define ISDIGIT(c) ((unsigned) (c) - '0' <= 9)
+#endif
+
+#include <errno.h>
+#if !STDC_HEADERS
+extern int errno;
+#endif
+
+#ifdef min
+#undef min
+#endif
+#ifdef max
+#undef max
+#endif
+#define min(a,b) ((a) <= (b) ? (a) : (b))
+#define max(a,b) ((a) >= (b) ? (a) : (b))
+
+/* This section contains Posix-compliant defaults for macros
+   that are meant to be overridden by hand in config.h as needed.  */
+
+#ifndef filename_cmp
+#define filename_cmp(a, b) strcmp (a, b)
+#endif
+
+#ifndef filename_lastdirchar
+#define filename_lastdirchar(filename) strrchr (filename, '/')
+#endif
+
+#ifndef HAVE_FORK
+#define HAVE_FORK 1
+#endif
+
+#ifndef HAVE_SETMODE
+#define HAVE_SETMODE 0
+#endif
+
+#ifndef initialize_main
+#define initialize_main(argcp, argvp)
+#endif
+
+/* Do struct stat *S, *T describe the same file?  Answer -1 if unknown.  */
+#ifndef same_file
+#define same_file(s,t) ((s)->st_ino==(t)->st_ino && (s)->st_dev==(t)->st_dev)
+#endif
+
+/* Place into Q a quoted version of A suitable for `popen' or `system',
+   incrementing Q and junking A.
+   Do not increment Q by more than 4 * strlen (A) + 2.  */
+#ifndef SYSTEM_QUOTE_ARG
+#define SYSTEM_QUOTE_ARG(q, a) \
+  { \
+    *(q)++ = '\''; \
+    for (;  *(a);  *(q)++ = *(a)++) \
+      if (*(a) == '\'') \
+	{ \
+	  *(q)++ = '\''; \
+	  *(q)++ = '\\'; \
+	  *(q)++ = '\''; \
+	} \
+    *(q)++ = '\''; \
+  }
+#endif
diff --git a/gnu/usr.bin/diff/util.c b/gnu/usr.bin/diff/util.c
new file mode 100644
index 00000000000..bbc3bff91a4
--- /dev/null
+++ b/gnu/usr.bin/diff/util.c
@@ -0,0 +1,754 @@
+/* Support routines for GNU DIFF.
+   Copyright (C) 1988, 1989, 1992, 1993, 1994 Free Software Foundation, Inc.
+
+This file is part of GNU DIFF.
+
+GNU DIFF is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU DIFF is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU DIFF; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "diff.h"
+
+#ifndef PR_PROGRAM
+#define PR_PROGRAM "/bin/pr"
+#endif
+
+/* Queue up one-line messages to be printed at the end,
+   when -l is specified.  Each message is recorded with a `struct msg'.  */
+
+struct msg
+{
+  struct msg *next;
+  char const *format;
+  char const *arg1;
+  char const *arg2;
+  char const *arg3;
+  char const *arg4;
+};
+
+/* Head of the chain of queues messages.  */
+
+static struct msg *msg_chain;
+
+/* Tail of the chain of queues messages.  */
+
+static struct msg **msg_chain_end = &msg_chain;
+
+/* Use when a system call returns non-zero status.
+   TEXT should normally be the file name.  */
+
+void
+perror_with_name (text)
+     char const *text;
+{
+  int e = errno;
+  fprintf (stderr, "%s: ", program_name);
+  errno = e;
+  perror (text);
+}
+
+/* Use when a system call returns non-zero status and that is fatal.  */
+
+void
+pfatal_with_name (text)
+     char const *text;
+{
+  int e = errno;
+  print_message_queue ();
+  fprintf (stderr, "%s: ", program_name);
+  errno = e;
+  perror (text);
+  exit (2);
+}
+
+/* Print an error message from the format-string FORMAT
+   with args ARG1 and ARG2.  */
+
+void
+error (format, arg, arg1)
+     char const *format, *arg, *arg1;
+{
+  fprintf (stderr, "%s: ", program_name);
+  fprintf (stderr, format, arg, arg1);
+  fprintf (stderr, "\n");
+}
+
+/* Print an error message containing the string TEXT, then exit.  */
+
+void
+fatal (m)
+     char const *m;
+{
+  print_message_queue ();
+  error ("%s", m, 0);
+  exit (2);
+}
+
+/* Like printf, except if -l in effect then save the message and print later.
+   This is used for things like "binary files differ" and "Only in ...".  */
+
+void
+message (format, arg1, arg2)
+     char const *format, *arg1, *arg2;
+{
+  message5 (format, arg1, arg2, 0, 0);
+}
+
+void
+message5 (format, arg1, arg2, arg3, arg4)
+     char const *format, *arg1, *arg2, *arg3, *arg4;
+{
+  if (paginate_flag)
+    {
+      struct msg *new = (struct msg *) xmalloc (sizeof (struct msg));
+      new->format = format;
+      new->arg1 = concat (arg1, "", "");
+      new->arg2 = concat (arg2, "", "");
+      new->arg3 = arg3 ? concat (arg3, "", "") : 0;
+      new->arg4 = arg4 ? concat (arg4, "", "") : 0;
+      new->next = 0;
+      *msg_chain_end = new;
+      msg_chain_end = &new->next;
+    }
+  else
+    {
+      if (sdiff_help_sdiff)
+	putchar (' ');
+      printf (format, arg1, arg2, arg3, arg4);
+    }
+}
+
+/* Output all the messages that were saved up by calls to `message'.  */
+
+void
+print_message_queue ()
+{
+  struct msg *m;
+
+  for (m = msg_chain; m; m = m->next)
+    printf (m->format, m->arg1, m->arg2, m->arg3, m->arg4);
+}
+
+/* Call before outputting the results of comparing files NAME0 and NAME1
+   to set up OUTFILE, the stdio stream for the output to go to.
+
+   Usually, OUTFILE is just stdout.  But when -l was specified
+   we fork off a `pr' and make OUTFILE a pipe to it.
+   `pr' then outputs to our stdout.  */
+
+static char const *current_name0;
+static char const *current_name1;
+static int current_depth;
+
+void
+setup_output (name0, name1, depth)
+     char const *name0, *name1;
+     int depth;
+{
+  current_name0 = name0;
+  current_name1 = name1;
+  current_depth = depth;
+  outfile = 0;
+}
+
+#if HAVE_FORK
+static pid_t pr_pid;
+#endif
+
+void
+begin_output ()
+{
+  char *name;
+
+  if (outfile != 0)
+    return;
+
+  /* Construct the header of this piece of diff.  */
+  name = xmalloc (strlen (current_name0) + strlen (current_name1)
+		  + strlen (switch_string) + 7);
+  /* Posix.2 section 4.17.6.1.1 specifies this format.  But there is a
+     bug in the first printing (IEEE Std 1003.2-1992 p 251 l 3304):
+     it says that we must print only the last component of the pathnames.
+     This requirement is silly and does not match historical practice.  */
+  sprintf (name, "diff%s %s %s", switch_string, current_name0, current_name1);
+
+  if (paginate_flag)
+    {
+      /* Make OUTFILE a pipe to a subsidiary `pr'.  */
+
+#if HAVE_FORK
+      int pipes[2];
+
+      if (pipe (pipes) != 0)
+	pfatal_with_name ("pipe");
+
+      fflush (stdout);
+
+      pr_pid = vfork ();
+      if (pr_pid < 0)
+	pfatal_with_name ("vfork");
+
+      if (pr_pid == 0)
+	{
+	  close (pipes[1]);
+	  if (pipes[0] != STDIN_FILENO)
+	    {
+	      if (dup2 (pipes[0], STDIN_FILENO) < 0)
+		pfatal_with_name ("dup2");
+	      close (pipes[0]);
+	    }
+
+	  execl (PR_PROGRAM, PR_PROGRAM, "-f", "-h", name, 0);
+	  pfatal_with_name (PR_PROGRAM);
+	}
+      else
+	{
+	  close (pipes[0]);
+	  outfile = fdopen (pipes[1], "w");
+	  if (!outfile)
+	    pfatal_with_name ("fdopen");
+	}
+#else /* ! HAVE_FORK */
+      char *command = xmalloc (4 * strlen (name) + strlen (PR_PROGRAM) + 10);
+      char *p;
+      char const *a = name;
+      sprintf (command, "%s -f -h ", PR_PROGRAM);
+      p = command + strlen (command);
+      SYSTEM_QUOTE_ARG (p, a);
+      *p = 0;
+      outfile = popen (command, "w");
+      if (!outfile)
+	pfatal_with_name (command);
+      free (command);
+#endif /* ! HAVE_FORK */
+    }
+  else
+    {
+
+      /* If -l was not specified, output the diff straight to `stdout'.  */
+
+      outfile = stdout;
+
+      /* If handling multiple files (because scanning a directory),
+	 print which files the following output is about.  */
+      if (current_depth > 0)
+	printf ("%s\n", name);
+    }
+
+  free (name);
+
+  /* A special header is needed at the beginning of context output.  */
+  switch (output_style)
+    {
+    case OUTPUT_CONTEXT:
+      print_context_header (files, 0);
+      break;
+
+    case OUTPUT_UNIFIED:
+      print_context_header (files, 1);
+      break;
+
+    default:
+      break;
+    }
+}
+
+/* Call after the end of output of diffs for one file.
+   Close OUTFILE and get rid of the `pr' subfork.  */
+
+void
+finish_output ()
+{
+  if (outfile != 0 && outfile != stdout)
+    {
+      int wstatus;
+      if (ferror (outfile))
+	fatal ("write error");
+#if ! HAVE_FORK
+      wstatus = pclose (outfile);
+#else /* HAVE_FORK */
+      if (fclose (outfile) != 0)
+	pfatal_with_name ("write error");
+      if (waitpid (pr_pid, &wstatus, 0) < 0)
+	pfatal_with_name ("waitpid");
+#endif /* HAVE_FORK */
+      if (wstatus != 0)
+	fatal ("subsidiary pr failed");
+    }
+
+  outfile = 0;
+}
+
+/* Compare two lines (typically one from each input file)
+   according to the command line options.
+   For efficiency, this is invoked only when the lines do not match exactly
+   but an option like -i might cause us to ignore the difference.
+   Return nonzero if the lines differ.  */
+
+int
+line_cmp (s1, s2)
+     char const *s1, *s2;
+{
+  register unsigned char const *t1 = (unsigned char const *) s1;
+  register unsigned char const *t2 = (unsigned char const *) s2;
+
+  while (1)
+    {
+      register unsigned char c1 = *t1++;
+      register unsigned char c2 = *t2++;
+
+      /* Test for exact char equality first, since it's a common case.  */
+      if (c1 != c2)
+	{
+	  /* Ignore horizontal white space if -b or -w is specified.  */
+
+	  if (ignore_all_space_flag)
+	    {
+	      /* For -w, just skip past any white space.  */
+	      while (ISSPACE (c1) && c1 != '\n') c1 = *t1++;
+	      while (ISSPACE (c2) && c2 != '\n') c2 = *t2++;
+	    }
+	  else if (ignore_space_change_flag)
+	    {
+	      /* For -b, advance past any sequence of white space in line 1
+		 and consider it just one Space, or nothing at all
+		 if it is at the end of the line.  */
+	      if (ISSPACE (c1))
+		{
+		  while (c1 != '\n')
+		    {
+		      c1 = *t1++;
+		      if (! ISSPACE (c1))
+			{
+			  --t1;
+			  c1 = ' ';
+			  break;
+			}
+		    }
+		}
+
+	      /* Likewise for line 2.  */
+	      if (ISSPACE (c2))
+		{
+		  while (c2 != '\n')
+		    {
+		      c2 = *t2++;
+		      if (! ISSPACE (c2))
+			{
+			  --t2;
+			  c2 = ' ';
+			  break;
+			}
+		    }
+		}
+
+	      if (c1 != c2)
+		{
+		  /* If we went too far when doing the simple test
+		     for equality, go back to the first non-white-space
+		     character in both sides and try again.  */
+		  if (c2 == ' ' && c1 != '\n'
+		      && (unsigned char const *) s1 + 1 < t1
+		      && ISSPACE(t1[-2]))
+		    {
+		      --t1;
+		      continue;
+		    }
+		  if (c1 == ' ' && c2 != '\n'
+		      && (unsigned char const *) s2 + 1 < t2
+		      && ISSPACE(t2[-2]))
+		    {
+		      --t2;
+		      continue;
+		    }
+		}
+	    }
+
+	  /* Lowercase all letters if -i is specified.  */
+
+	  if (ignore_case_flag)
+	    {
+	      if (ISUPPER (c1))
+		c1 = tolower (c1);
+	      if (ISUPPER (c2))
+		c2 = tolower (c2);
+	    }
+
+	  if (c1 != c2)
+	    break;
+	}
+      if (c1 == '\n')
+	return 0;
+    }
+
+  return (1);
+}
+
+/* Find the consecutive changes at the start of the script START.
+   Return the last link before the first gap.  */
+
+struct change *
+find_change (start)
+     struct change *start;
+{
+  return start;
+}
+
+struct change *
+find_reverse_change (start)
+     struct change *start;
+{
+  return start;
+}
+
+/* Divide SCRIPT into pieces by calling HUNKFUN and
+   print each piece with PRINTFUN.
+   Both functions take one arg, an edit script.
+
+   HUNKFUN is called with the tail of the script
+   and returns the last link that belongs together with the start
+   of the tail.
+
+   PRINTFUN takes a subscript which belongs together (with a null
+   link at the end) and prints it.  */
+
+void
+print_script (script, hunkfun, printfun)
+     struct change *script;
+     struct change * (*hunkfun) PARAMS((struct change *));
+     void (*printfun) PARAMS((struct change *));
+{
+  struct change *next = script;
+
+  while (next)
+    {
+      struct change *this, *end;
+
+      /* Find a set of changes that belong together.  */
+      this = next;
+      end = (*hunkfun) (next);
+
+      /* Disconnect them from the rest of the changes,
+	 making them a hunk, and remember the rest for next iteration.  */
+      next = end->link;
+      end->link = 0;
+#ifdef DEBUG
+      debug_script (this);
+#endif
+
+      /* Print this hunk.  */
+      (*printfun) (this);
+
+      /* Reconnect the script so it will all be freed properly.  */
+      end->link = next;
+    }
+}
+
+/* Print the text of a single line LINE,
+   flagging it with the characters in LINE_FLAG (which say whether
+   the line is inserted, deleted, changed, etc.).  */
+
+void
+print_1_line (line_flag, line)
+     char const *line_flag;
+     char const * const *line;
+{
+  char const *text = line[0], *limit = line[1]; /* Help the compiler.  */
+  FILE *out = outfile; /* Help the compiler some more.  */
+  char const *flag_format = 0;
+
+  /* If -T was specified, use a Tab between the line-flag and the text.
+     Otherwise use a Space (as Unix diff does).
+     Print neither space nor tab if line-flags are empty.  */
+
+  if (line_flag && *line_flag)
+    {
+      flag_format = tab_align_flag ? "%s\t" : "%s ";
+      fprintf (out, flag_format, line_flag);
+    }
+
+  output_1_line (text, limit, flag_format, line_flag);
+
+  if ((!line_flag || line_flag[0]) && limit[-1] != '\n')
+    fprintf (out, "\n\\ No newline at end of file\n");
+}
+
+/* Output a line from TEXT up to LIMIT.  Without -t, output verbatim.
+   With -t, expand white space characters to spaces, and if FLAG_FORMAT
+   is nonzero, output it with argument LINE_FLAG after every
+   internal carriage return, so that tab stops continue to line up.  */
+
+void
+output_1_line (text, limit, flag_format, line_flag)
+     char const *text, *limit, *flag_format, *line_flag;
+{
+  if (!tab_expand_flag)
+    fwrite (text, sizeof (char), limit - text, outfile);
+  else
+    {
+      register FILE *out = outfile;
+      register unsigned char c;
+      register char const *t = text;
+      register unsigned column = 0;
+
+      while (t < limit)
+	switch ((c = *t++))
+	  {
+	  case '\t':
+	    {
+	      unsigned spaces = TAB_WIDTH - column % TAB_WIDTH;
+	      column += spaces;
+	      do
+		putc (' ', out);
+	      while (--spaces);
+	    }
+	    break;
+
+	  case '\r':
+	    putc (c, out);
+	    if (flag_format && t < limit && *t != '\n')
+	      fprintf (out, flag_format, line_flag);
+	    column = 0;
+	    break;
+
+	  case '\b':
+	    if (column == 0)
+	      continue;
+	    column--;
+	    putc (c, out);
+	    break;
+
+	  default:
+	    if (ISPRINT (c))
+	      column++;
+	    putc (c, out);
+	    break;
+	  }
+    }
+}
+
+int
+change_letter (inserts, deletes)
+     int inserts, deletes;
+{
+  if (!inserts)
+    return 'd';
+  else if (!deletes)
+    return 'a';
+  else
+    return 'c';
+}
+
+/* Translate an internal line number (an index into diff's table of lines)
+   into an actual line number in the input file.
+   The internal line number is LNUM.  FILE points to the data on the file.
+
+   Internal line numbers count from 0 starting after the prefix.
+   Actual line numbers count from 1 within the entire file.  */
+
+int
+translate_line_number (file, lnum)
+     struct file_data const *file;
+     int lnum;
+{
+  return lnum + file->prefix_lines + 1;
+}
+
+void
+translate_range (file, a, b, aptr, bptr)
+     struct file_data const *file;
+     int a, b;
+     int *aptr, *bptr;
+{
+  *aptr = translate_line_number (file, a - 1) + 1;
+  *bptr = translate_line_number (file, b + 1) - 1;
+}
+
+/* Print a pair of line numbers with SEPCHAR, translated for file FILE.
+   If the two numbers are identical, print just one number.
+
+   Args A and B are internal line numbers.
+   We print the translated (real) line numbers.  */
+
+void
+print_number_range (sepchar, file, a, b)
+     int sepchar;
+     struct file_data *file;
+     int a, b;
+{
+  int trans_a, trans_b;
+  translate_range (file, a, b, &trans_a, &trans_b);
+
+  /* Note: we can have B < A in the case of a range of no lines.
+     In this case, we should print the line number before the range,
+     which is B.  */
+  if (trans_b > trans_a)
+    fprintf (outfile, "%d%c%d", trans_a, sepchar, trans_b);
+  else
+    fprintf (outfile, "%d", trans_b);
+}
+
+/* Look at a hunk of edit script and report the range of lines in each file
+   that it applies to.  HUNK is the start of the hunk, which is a chain
+   of `struct change'.  The first and last line numbers of file 0 are stored in
+   *FIRST0 and *LAST0, and likewise for file 1 in *FIRST1 and *LAST1.
+   Note that these are internal line numbers that count from 0.
+
+   If no lines from file 0 are deleted, then FIRST0 is LAST0+1.
+
+   Also set *DELETES nonzero if any lines of file 0 are deleted
+   and set *INSERTS nonzero if any lines of file 1 are inserted.
+   If only ignorable lines are inserted or deleted, both are
+   set to 0.  */
+
+void
+analyze_hunk (hunk, first0, last0, first1, last1, deletes, inserts)
+     struct change *hunk;
+     int *first0, *last0, *first1, *last1;
+     int *deletes, *inserts;
+{
+  int l0, l1, show_from, show_to;
+  int i;
+  int trivial = ignore_blank_lines_flag || ignore_regexp_list;
+  struct change *next;
+
+  show_from = show_to = 0;
+
+  *first0 = hunk->line0;
+  *first1 = hunk->line1;
+
+  next = hunk;
+  do
+    {
+      l0 = next->line0 + next->deleted - 1;
+      l1 = next->line1 + next->inserted - 1;
+      show_from += next->deleted;
+      show_to += next->inserted;
+
+      for (i = next->line0; i <= l0 && trivial; i++)
+	if (!ignore_blank_lines_flag || files[0].linbuf[i][0] != '\n')
+	  {
+	    struct regexp_list *r;
+	    char const *line = files[0].linbuf[i];
+	    int len = files[0].linbuf[i + 1] - line;
+
+	    for (r = ignore_regexp_list; r; r = r->next)
+	      if (0 <= re_search (&r->buf, line, len, 0, len, 0))
+		break;	/* Found a match.  Ignore this line.  */
+	    /* If we got all the way through the regexp list without
+	       finding a match, then it's nontrivial.  */
+	    if (!r)
+	      trivial = 0;
+	  }
+
+      for (i = next->line1; i <= l1 && trivial; i++)
+	if (!ignore_blank_lines_flag || files[1].linbuf[i][0] != '\n')
+	  {
+	    struct regexp_list *r;
+	    char const *line = files[1].linbuf[i];
+	    int len = files[1].linbuf[i + 1] - line;
+
+	    for (r = ignore_regexp_list; r; r = r->next)
+	      if (0 <= re_search (&r->buf, line, len, 0, len, 0))
+		break;	/* Found a match.  Ignore this line.  */
+	    /* If we got all the way through the regexp list without
+	       finding a match, then it's nontrivial.  */
+	    if (!r)
+	      trivial = 0;
+	  }
+    }
+  while ((next = next->link) != 0);
+
+  *last0 = l0;
+  *last1 = l1;
+
+  /* If all inserted or deleted lines are ignorable,
+     tell the caller to ignore this hunk.  */
+
+  if (trivial)
+    show_from = show_to = 0;
+
+  *deletes = show_from;
+  *inserts = show_to;
+}
+
+/* malloc a block of memory, with fatal error message if we can't do it. */
+
+VOID *
+xmalloc (size)
+     size_t size;
+{
+  register VOID *value;
+
+  if (size == 0)
+    size = 1;
+
+  value = (VOID *) malloc (size);
+
+  if (!value)
+    fatal ("memory exhausted");
+  return value;
+}
+
+/* realloc a block of memory, with fatal error message if we can't do it. */
+
+VOID *
+xrealloc (old, size)
+     VOID *old;
+     size_t size;
+{
+  register VOID *value;
+
+  if (size == 0)
+    size = 1;
+
+  value = (VOID *) realloc (old, size);
+
+  if (!value)
+    fatal ("memory exhausted");
+  return value;
+}
+
+/* Concatenate three strings, returning a newly malloc'd string.  */
+
+char *
+concat (s1, s2, s3)
+     char const *s1, *s2, *s3;
+{
+  size_t len = strlen (s1) + strlen (s2) + strlen (s3);
+  char *new = xmalloc (len + 1);
+  sprintf (new, "%s%s%s", s1, s2, s3);
+  return new;
+}
+
+/* Yield the newly malloc'd pathname
+   of the file in DIR whose filename is FILE.  */
+
+char *
+dir_file_pathname (dir, file)
+     char const *dir, *file;
+{
+  char const *p = filename_lastdirchar (dir);
+  return concat (dir, "/" + (p && !p[1]), file);
+}
+
+void
+debug_script (sp)
+     struct change *sp;
+{
+  fflush (stdout);
+  for (; sp; sp = sp->link)
+    fprintf (stderr, "%3d %3d delete %d insert %d\n",
+	     sp->line0, sp->line1, sp->deleted, sp->inserted);
+  fflush (stderr);
+}
diff --git a/gnu/usr.bin/diff/version.c b/gnu/usr.bin/diff/version.c
new file mode 100644
index 00000000000..02993976351
--- /dev/null
+++ b/gnu/usr.bin/diff/version.c
@@ -0,0 +1,5 @@
+/* Version number of GNU diff.  */
+
+#include <config.h>
+
+char const version_string[] = "2.7";