Add a run-time Test for proper operation of re_compile_pattern.

[pspp] / m4 / regex.m4

diff --git a/m4/regex.m4 b/m4/regex.m4
index 007b166364f40b402cdf9953f302b0582ff58da4..b7a0389420305b0793cd6ed5965cbca587f04f65 100644 (file)
--- a/m4/regex.m4
+++ b/m4/regex.m4
@@ -1,37 +1,71 @@
-## --------------------------------- ##
-## Check if --with-regex was given.  ##
-## --------------------------------- ##
-
-# serial 1
-
-# The idea is to distribute rx.[hc] and regex.[hc] together, for a while.
-# The WITH_REGEX symbol (which should also be documented in acconfig.h)
-# is used to decide which of regex.h or rx.h should be included in the
-# application.  If `./configure --with-regex' is given (the default), the
-# package will use gawk's regex.  If `./configure --without-regex', a
-# check is made to see if rx is already installed, as with newer Linux'es.
-# If not found, the package will use the rx from the distribution.
-# If found, the package will use the system's rx which, on Linux at least,
-# will result in a smaller executable file.
-
-AC_DEFUN(AM_WITH_REGEX,
-[AC_MSG_CHECKING(which of GNU rx or gawk's regex is wanted)
-AC_ARG_WITH(regex,
-[  --without-regex         use GNU rx in lieu of gawk's regex for matching],
-[test "$withval" = yes && am_with_regex=1],
-[am_with_regex=1])
-if test -n "$am_with_regex"; then
-  AC_MSG_RESULT(regex)
-  AC_DEFINE(WITH_REGEX)
-  AC_CACHE_CHECK([for GNU regex in libc], am_cv_gnu_regex,
-    AC_TRY_LINK([], [extern int re_max_failures; re_max_failures = 1],
-               am_cv_gnu_regex=yes, am_cv_gnu_regex=no))
-  if test $am_cv_gnu_regex = no; then
-    LIBOBJS="$LIBOBJS regex.o"
-  fi
-else
-  AC_MSG_RESULT(rx)
-  AC_CHECK_FUNC(re_rx_search, , [LIBOBJS="$LIBOBJS rx.o"])
-fi
-AC_SUBST(LIBOBJS)dnl
-])
+#serial 4
+
+dnl Initially derived from code in GNU grep.
+dnl Mostly written by Jim Meyering.
+
+AC_DEFUN(jm_WITH_REGEX,
+  [
+    AC_REQUIRE([AM_GLIBC])
+
+    dnl Even packages that don't use regex.c can use this macro.
+    dnl Of course, for them it doesn't do anything.
+
+    # By default, don't use the included regex.c on systems with a version
+    # of glibc 2 that's new enough to pass the following run test.
+    # If cross compiling, assume the test would fail and use the included
+    # regex.c.  The failing regular expression is from `Spencer ere test
+    # #75' in grep-2.2f.
+    ac_use_included_regex=yes
+
+    if test "$ac_cv_glibc" = yes; then
+      # Without this run-test, on older glibc2 systems we'd end up
+      # using the buggy system regex.
+      AC_CACHE_CHECK([for working re_compile_pattern],
+                     jm_cv_func_working_re_compile_pattern,
+       AC_TRY_RUN(
+         changequote(<<, >>)dnl
+         <<
+#include <stdio.h>
+#include <regex.h>
+           int
+           main ()
+           {
+             static struct re_pattern_buffer regex;
+             const char *s;
+             re_set_syntax (RE_SYNTAX_POSIX_EGREP);
+             /* Add this third left square bracket, [, to balance the
+                three right ones below.  Otherwise autoconf-2.14 chokes.  */
+             s = re_compile_pattern ("a[[:]:]]b\n", 9, &regex);
+             /* This should fail with _Invalid character class name_ error.  */
+             exit (s ? 0 : 1);
+           }
+         >>,
+         changequote([, ])dnl
+
+                jm_cv_func_working_re_compile_pattern=yes,
+                jm_cv_func_working_re_compile_pattern=no,
+                dnl When crosscompiling, assume it's broken.
+                jm_cv_func_working_re_compile_pattern=no))
+      if test $jm_cv_func_working_re_compile_pattern = yes; then
+       ac_use_included_regex=no
+      fi
+    fi
+
+    test -n "$1" || AC_MSG_ERROR([missing argument])
+    syscmd([test -f $1])
+    ifelse(sysval, 0,
+      [
+
+       AC_ARG_WITH(included-regex,
+       [  --without-included-regex don't compile regex; this is the default on
+                          systems with version 2 of the GNU C library
+                          (use with caution on other system)],
+                   jm_with_regex=$withval,
+                   jm_with_regex=$ac_use_included_regex)
+       if test "$jm_with_regex" = yes; then
+         LIBOBJS="$LIBOBJS regex.o"
+       fi
+      ],
+    )
+  ]
+)