[groff] 07/08: PROBLEMS: Warn about gdiffmk/expr/FreeBSD problem.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 405fe32847a598962dc3ad8469b9ed0bac4c50ba
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Mon Mar 6 12:27:18 2023 -0600

    PROBLEMS: Warn about gdiffmk/expr/FreeBSD problem.
---
 PROBLEMS | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/PROBLEMS b/PROBLEMS
index 471e4a526..0aa428f09 100644
--- a/PROBLEMS
+++ b/PROBLEMS
@@ -115,6 +115,20 @@ malfunction.  See 
<https://debbugs.gnu.org/db/61/61193.html>.
 
 ----------------------------------------------------------------------
 
+* gdiffmk doesn't work on FreeBSD; I get errors from "expr".
+
+gdiffmk uses the expr(1) command to parse its arguments.  FreeBSD has
+extended the syntax of its expr command in a non-backward compatible way
+that it claims better conforms with POSIX's utility syntax guidelines
+with respect to option processing: however, POSIX mandates no options
+for expr.  Other implementations of expr do not support traditional
+Unix-style options ('-a', '-b', ...), and perhaps as a consequence do
+not follow FreeBSD's interpretation of the guidelines.  You way want to
+set $EXPR_COMPAT in your shell environment.  We hope to have a
+workaround for this behavior in a future release.
+
+----------------------------------------------------------------------
+
 * My document says that the current year is 19100, not 2000.
 
 In groff, as in traditional troff, the yr number register yields the