By default, don't use the included regex.c on systems

with glibc 2.  Suggestion from Uli Drepper.

diff --git a/m4/regex.m4 b/m4/regex.m4
index e5468c6..2a638d6 100644 (file)
--- a/m4/regex.m4
+++ b/m4/regex.m4
@@ -1,19 +1,26 @@
-#serial 2
+#serial 3
 
 dnl Derived from code in GNU grep.
 
 AC_DEFUN(jm_WITH_REGEX,
   [
+    AC_REQUIRE([AM_GLIBC])
+
     dnl Even packages that don't use regex.c can use this macro.
     dnl Of course, for them it doesn't do anything.
 
     syscmd([test -f lib/regex.c])
     ifelse(sysval, 0,
       [
+       # By default, don't use the included regex.c on systems with glibc 2
+       test "$ac_cv_glibc" = yes && default=no || default=yes
+
        AC_ARG_WITH(included-regex,
-           [  --without-included-regex don't compile regex (use with caution)],
+       [  --without-included-regex don't compile regex; this is the default on
+                          systems with version 2 of the GNU C library
+                          (use with caution on other system)],
                    jm_with_regex=$withval,
-                   jm_with_regex=yes)
+                   jm_with_regex=$default)
        if test "$jm_with_regex" = yes; then
          LIBOBJS="$LIBOBJS regex.o"
        fi