gnulib: Add modules argmatch and isatty.

* lib/argmatch.c, lib/argmatch.h, lib/c-ctype.c, lib/c-ctype.h,
lib/config.charset, lib/c-strcasecmp.c, lib/c-strcaseeq.h,
lib/c-strcase.h, lib/c-strncasecmp.c, lib/exitfail.c, lib/exitfail.h,
lib/isatty.c, lib/localcharset.c, lib/localcharset.h, lib/mbrtowc.c,
lib/mbsinit.c, lib/quotearg.c, lib/quotearg.h, lib/quote.h,
lib/ref-add.sin, lib/ref-del.sin, lib/streq.h, lib/wctype-h.c,
lib/wctype.in.h, lib/xalloc-die.c, lib/xalloc.h, lib/xalloc-oversized.h,
lib/xmalloc.c, m4/codeset.m4, m4/configmake.m4, m4/glibc21.m4,
m4/isatty.m4, m4/localcharset.m4, m4/locale-fr.m4, m4/locale-ja.m4,
m4/locale-zh.m4, m4/mbrtowc.m4, m4/mbsinit.m4, m4/mbstate_t.m4,
m4/quotearg.m4, m4/quote.m4, m4/wctype_h.m4, m4/xalloc.m4: New files.
* lib/Makefile.am, m4/gnulib-cache.m4, m4/gnulib-comp.m4: Update.

lib/exitfail.h

@@ -0,0 +1,18 @@
+/* Failure exit status
+
+   Copyright (C) 2002, 2009-2013 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+extern int volatile exit_failure;