Compiling glibc fails on Gentoo with gcc 4.1 must provide cpuid.h

Upgrading Gentoo is a bitch (see below). Follow these steps to get glibc to compile if you're getting an error about gcc not providing cpuid.h:

# emerge -v gcc
# gcc-config -l (lists gcc profiles; select the newest gcc you see in the list)
# gcc-config 2 (where 2 is the number of the newest profile from above)
# source /etc/profile
# emerge -v glibc

The package glibc should now complile and install (emerge) without any further gcc related issues.