Get the src.rpm, install it, edit the spec, rebuild.
I am using the srpm... I was able to do this in CentOS 4.1, but 4.2 x86_64 has been problematic so far.
I was speeking of the centosplus src.rpm - to be build on a system with no i[3456]86 packages except for those 2 glibc packages.
MaZe.