Add native Windows binary for bison.

bison/src/bison/2.4.1/bison-2.4.1-src/lib/dup-safer.c

+/* Invoke dup, but avoid some glitches.
+
+   Copyright (C) 2001, 2004, 2005, 2006 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/>.  */
+
+/* Written by Paul Eggert.  */
+
+#include <config.h>
+
+#include "unistd-safer.h"
+
+#include <fcntl.h>
+
+#include <unistd.h>
+#ifndef STDERR_FILENO
+# define STDERR_FILENO 2
+#endif
+
+/* Like dup, but do not return STDIN_FILENO, STDOUT_FILENO, or
+   STDERR_FILENO.  */
+
+int
+dup_safer (int fd)
+{
+#if defined F_DUPFD && !defined FCHDIR_REPLACEMENT
+  return fcntl (fd, F_DUPFD, STDERR_FILENO + 1);
+#else
+  /* fd_safer calls us back, but eventually the recursion unwinds and
+     does the right thing.  */
+  return fd_safer (dup (fd));
+#endif
+}