Use Gnulib's `localcharset', with local patches.

This follows Bruno Haible's suggestion at
<http://lists.gnu.org/archive/html/guile-devel/2011-11/msg00055.html>.

* m4/gnulib-cache.m4: Add `gl_LOCAL_DIR'; use `localcharset'.

* Makefile.am (EXTRA_DIST): Add gnulib-local/lib/localcharset.[ch].diff.
  (TESTS_ENVIRONMENT): New variable.

* gnulib-local/lib/localcharset.c.diff,
  gnulib-local/lib/localcharset.h.diff: New files.

* test-suite/Makefile.am (TESTS_ENVIRONMENT): Add
  @LOCALCHARSET_TESTS_ENVIRONMENT@.
* test-suite/standalone/Makefile.am (TESTS_ENVIRONMENT): Likewise.

1 files changed, 47 insertions, 0 deletions

diff --git a/lib/localcharset.h b/lib/localcharset.h
new file mode 100644
index 000000000..a80c8cbf5
--- /dev/null
+++ b/lib/localcharset.h
@@ -0,0 +1,47 @@
+/* Determine a canonical name for the current locale's character encoding.
+   Copyright (C) 2000-2003, 2009-2011 Free Software Foundation, Inc.
+   This file is part of the GNU CHARSET Library.
+
+   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 2, 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, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#ifndef _LOCALCHARSET_H
+#define _LOCALCHARSET_H
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/* Determine the current locale's character encoding, and canonicalize it
+   into one of the canonical names listed in config.charset.
+   The result must not be freed; it is statically allocated.
+   If the canonical name cannot be determined, the result is a non-canonical
+   name.  */
+extern const char * locale_charset (void);
+
+/* Same as above, but only look at environment variables, avoiding calls to
+   `setlocale', `nl_langinfo', etc.  See
+   <http://lists.gnu.org/archive/html/guile-devel/2011-11/msg00040.html> for
+   the rationale.  */
+extern const char * environ_locale_charset (void);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif /* _LOCALCHARSET_H */