MFC r255107;

MFC r255107;

Add support for the GCC binary integer constants extension.

This is required to build the i965 backend with newer versions of mesa.

Original patch from Joerg Wunsch in GCC Bug 23479, under the GPLv2;
also taken from there in OpenBSD.

Obtained from:	gcc 4.3 (rev. 125346; GPLv2)

git-svn-id: svn://svn.freebsd.org/base/stable/8@258532 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f