First steps towards supporting W32.

This is mainly source code reorganization.
Update gnulib.
g10/ does currently not build.

gl/strpbrk.h

@@ -0,0 +1,28 @@
+/* Searching in a string.
+   Copyright (C) 2001-2002 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 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 General Public License for more details.
+
+   You should have received a copy of the GNU 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.  */
+
+#if HAVE_STRPBRK
+
+/* Get strpbrk() declaration.  */
+#include <string.h>
+
+#else
+
+/* Find the first occurrence in S of any character in ACCEPT.  */
+extern char *strpbrk (const char *s, const char *accept);
+
+#endif