Add native Windows binary for bison.

bison/contrib/bison/2.4.1/bison-2.4.1-src/README

+This package contains the GNU Bison parser generator.
+
+See the file INSTALL for generic compilation and installation instructions.
+
+See the section FAQ in the documentation (doc/bison.info) for
+frequently asked questions.  The documentation is also available in
+PDF and HTML, provided you have a recent version of Texinfo installed:
+run "make pdf" or "make html".
+
+Bison requires GNU m4 1.4.6 or later.  See:
+
+ftp://ftp.gnu.org/gnu/m4/m4-1.4.6.tar.gz
+
+Bison can work with pre-1.4.6 distributions of GNU m4 if they are
+sufficiently patched, but if you encounter a bug with an older
+distribution and report a bug we will probably suggest that you
+upgrade to 1.4.6 as the first step in trying to fix it.
+
+Please send bug reports to <bug-bison@gnu.org>.  Please include the
+version number from `bison --version', and a complete, self-contained
+test case in each bug report.
+
+If you have questions about using Bison and the documentation does
+not answer them, please send mail to <help-bison@gnu.org>.
+
+-----
+
+Copyright (C) 1992, 1998, 1999, 2003, 2004, 2005, 2008 Free Software Foundation, Inc.
+
+This file is part of Bison, the GNU Compiler Compiler.
+
+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/>.