From 18f8ae4bbed4d919e564fe54b94feb6bce2c4c8f Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering@redhat.com>
Date: Tue, 19 Jan 2010 08:25:12 +0100
Subject: [PATCH] ensure that the regexp [b-a] is diagnosed as invalid

* m4/regex.m4 (gl_REGEX): Ensure that re_compiler_pattern
diagnoses [b-a] as invalid when using RE_SYNTAX_POSIX_EGREP.
Currently, glibc-2.11.90-10 fails to do that.
---
 m4/regex.m4 | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/m4/regex.m4 b/m4/regex.m4
index a70225247..6bd6b8f7d 100644
--- a/m4/regex.m4
+++ b/m4/regex.m4
@@ -96,6 +96,13 @@ AC_DEFUN([gl_REGEX],
             if (!s)
               return 1;
 
+            /* Ensure that [b-a] is diagnosed as invalid. */
+            re_set_syntax (RE_SYNTAX_POSIX_EGREP);
+            memset (&regex, 0, sizeof regex);
+            s = re_compile_pattern ("a[b-a]", 6, &regex);
+            if (s == 0)
+              return 1;
+
             /* This should succeed, but does not for glibc-2.1.3.  */
             memset (&regex, 0, sizeof regex);
             s = re_compile_pattern ("{1", 2, &regex);
-- 
2.11.0