(ARGMATCH_DIE): Provide default.

[gnulib.git] / m4 / regex.m4

diff --git a/m4/regex.m4 b/m4/regex.m4
index 0d55c44..2a638d6 100644 (file)
--- a/m4/regex.m4
+++ b/m4/regex.m4
@@ -1,16 +1,30 @@
-#serial 1
+#serial 3
 
-dnl From grep.
+dnl Derived from code in GNU grep.
 
 AC_DEFUN(jm_WITH_REGEX,
   [
-    AC_ARG_WITH(included-regex,
-               [  --without-included-regex don't compile regex],
-               jm_with_regex=$withval,
-               jm_with_regex=yes)
+    AC_REQUIRE([AM_GLIBC])
 
-    if test "$jm_with_regex" = yes; then
-      LIBOBJS="$LIBOBJS regex.o"
-    fi
+    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 "$ac_cv_glibc" = yes && default=no || default=yes
+
+       AC_ARG_WITH(included-regex,
+       [  --without-included-regex don't compile regex; this is the default on
+                          systems with version 2 of the GNU C library
+                          (use with caution on other system)],
+                   jm_with_regex=$withval,
+                   jm_with_regex=$default)
+       if test "$jm_with_regex" = yes; then
+         LIBOBJS="$LIBOBJS regex.o"
+       fi
+      ],
+    )
   ]
 )