Support negative indentations for mdoc(7) displays and lists.

Not exactly recommended for use, rather for groff compatibility.
While here, introduce similar SHRT_MAX limits as in man(7),
fixing a few cases of infinite output found by jsg@ with afl.

1 files changed, 21 insertions, 0 deletions

diff --git a/regress/usr.bin/mandoc/mdoc/Bd/offset-neg.out_ascii b/regress/usr.bin/mandoc/mdoc/Bd/offset-neg.out_ascii
new file mode 100644
index 00000000000..0ecf61cf48f
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Bd/offset-neg.out_ascii
@@ -0,0 +1,21 @@
+BD-INDENT(1)                General Commands Manual               BD-INDENT(1)
+
+NNAAMMEE
+     BBdd--iinnddeenntt - indenting display blocks
+
+DDEESSCCRRIIPPTTIIOONN
+     regular text
+
+             outer display
+
+        inner display
+             outer display
+     regular text
+
+  outer display
+
+          inner display
+  outer display
+     regular text
+
+OpenBSD                        December 24, 2014                       OpenBSD