[PATCH] biarch compiler support for i386

This allows the i386 architecture to be built on a system with a biarch
compiler that defaults to x86-64, merely by specifying ARCH=i386.

As previously discussed, this uses the equivalent logic to the ppc port.

Signed-Off-By: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>