Use Gnulib's `regex' module.

This should help with regex portability, as reported in
<http://bugs.gnu.org/10684> for Darwin 8.11.

* m4/gnulib-cache.m4 (gl_MODULES): Add `regex'.

* configure.ac: Remove header checks for regex.h, rxposix.h, and
  rx/rxposix.h.  Remove check for the `regcomp' function.  Remove
  definition of `HAVE_REGCOMP'.  Define `ENABLE_REGEX'.

* libguile/init.c: Check for `ENABLE_REGEX' instead of `HAVE_REGCOMP'.

* libguile/regex-posix.c: Always include <regex.h>.  Remove #ifdefs for
  rxposix.h and co.

1 files changed, 44 insertions, 0 deletions

diff --git a/lib/mbtowc-impl.h b/lib/mbtowc-impl.h
new file mode 100644
index 000000000..3183f918a
--- /dev/null
+++ b/lib/mbtowc-impl.h
@@ -0,0 +1,44 @@
+/* Convert multibyte character to wide character.
+   Copyright (C) 2011-2012 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2011.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* We don't need a static internal state, because the encoding is not state
+   dependent, and when mbrtowc returns (size_t)(-2). we throw the result
+   away. */
+
+int
+mbtowc (wchar_t *pwc, const char *s, size_t n)
+{
+  if (s == NULL)
+    return 0;
+  else
+    {
+      mbstate_t state;
+      wchar_t wc;
+      size_t result;
+
+      memset (&state, 0, sizeof (mbstate_t));
+      result = mbrtowc (&wc, s, n, &state);
+      if (result == (size_t)-1 || result == (size_t)-2)
+        {
+          errno = EILSEQ;
+          return -1;
+        }
+      if (pwc != NULL)
+        *pwc = wc;
+      return (wc == 0 ? 0 : result);
+    }
+}