@twobob: One way to do that, while keeping the tricks to a minimum, and still using a decent GCC version, would be to find the latest GCC version that can be used to build glibc 2.5. (It's still in ct-ng, IIRC. if not, it's pretty easy to fix, since it was at one point

).
I don't *think* it builds properly with GCC 4.7, but I might be wrong, been a while since I tried.