Add thread-safety to libc, so that libc_r will build (on i386 at least).

All POSIX libc api now there (to P1003.1c/D10)
  (more md stuff is needed for other libc/arch/*)
  (setlogin is no longer a special syscall)
Add -pthread option to gcc (that makes it use -lc_r and -D_POSIX_THREADS).
Doc some re-entrant routines
Add libc_r to intro(3)
dig() uses some libc srcs and an extra -I was needed there.
Add more md stuff to libc_r.
Update includes for the pthreads api
Update libc_r TODO

1 files changed, 10 insertions, 2 deletions

diff --git a/lib/libc/gen/isatty.c b/lib/libc/gen/isatty.c
index d4dc9ad6cf6..f32cf3eaeb5 100644
--- a/lib/libc/gen/isatty.c
+++ b/lib/libc/gen/isatty.c
@@ -32,17 +32,25 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
-static char rcsid[] = "$OpenBSD: isatty.c,v 1.2 1996/08/19 08:24:32 tholo Exp $";
+static char rcsid[] = "$OpenBSD: isatty.c,v 1.3 1998/11/20 11:18:39 d Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 #include <termios.h>
 #include <unistd.h>
+#include "thread_private.h"
 
 int
 isatty(fd)
 	int fd;
 {
+	int retval;
 	struct termios t;
 
-	return(tcgetattr(fd, &t) != -1);
+	if (_FD_LOCK(fd, FD_READ, NULL) == 0) {
+		retval = (tcgetattr(fd, &t) != -1);
+		_FD_UNLOCK(fd, FD_READ);
+	} else {
+		retval = 0;
+	}
+	return(retval);
 }