Ulrich Drepper recommended that we not work on glibc 2.1 but use glibc 2.2 instead. I've checked a version out of sourceware.cygnus.com and I'm importing it to puffin.external.hp.com right now. I'll post a recipe for building it later (it doesn't build yet for me, but it gets a lot further than glibc 2.1 did)