glibc's --with-cpu option

Question

I'm unable to compile glibc: configure exits with the following error:

configure: error: The [CPU] subspecies of x86_64 is not supported.

I'm sorry; this must be somewhere, but I haven't been able to find it. I've searched a lot, but had no luck. I've even tried

echo 'int main(void){return 0;}' | gcc -x c -mcpu=[CPU] -

CPU worked in some cases where glibc's configure --with-cpu= failed. That confuses me a lot: doesn't that option take a value that is directly passed to the compiler via -mcpu=?

My processor is an AMD Turion X2 Dual-Core Mobile RM-70, and it would be lovely to know what the hell its "code" is. I don't know if I would need some kind of patch... Maybe I'm passing the wrong code for my processor! This makes me feel angry. Either there's not enough documentation or I'm missing something essential!

Building on ArchLinux using the Arch Build System (makepkg), PKGBUILD not hacked very much (not enough to break a build this way, I guess); glibc version 2.17; gcc 4.7.2. It also failed in the past so I guess the problem is not with versioning but with my understanding.

Best regards, Kalrish