I try and do my best to help out with testing Gentoo on my range of different machines. One of them is an Intel Itanium 2.

I had been having issues building glibc. A friendly user on the IRC channel debugged this. He wrote a blog post about it that is well worth the read, even if you don't use IA64 machines.

trofi's blog :: glibc on ia64 or how relocations bootstrap

This is the GCC bug report
The Gentoo bug report

This is the GCC fix

Thanks slyfox/trofi for such a detailed write up. This has helped me.