[3.3]: Add Intel 64bit support

[Gabriel Dos Reis]

"H. J. Lu" <hjl@lucon.org> writes:

| Hi Gaby,
| 
| I'd like to backport Intel 64bit support from mainline so that people
| can use --with-cpu=nocona and -march=nocona for gcc 3.5, gcc 3.4 and
| gcc 3.3. The patch is in the bug report:
| 
| http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14723

OK.