/var/tmp/portage/sys-libs/glibc-2.9_p20081201-r2/temp/environment: line 1275: eblit-glibc-src_install: command not found
emerge happily continued, and deleted my existing glibc install. Too much is broken now, except I still had a terminal and browser window open so I can at least let you know about this.
No, I cannot get you emerge --info or a build log, at least not now. I'm too busy recovering my system.
Why don't you just emerge a precompiled binary glibc to see if it solves your problem?
I didn't do that because I didn't have a boot CD, and because booting into busybox I didn't manage to get net access to download anything. I gave up, booted into NetBSD (installed only a week ago, thankfully) and untarred a stage3 over my existing system (copying glibc only failed horribly because it was an older version than what I was running). From there, my system was bootable and while I'm still in the process of fixing the mess, at least the important things are working again.
As for the bug, there haven't been any recent changes in glibc that might've caused this, as far as I've seen, so I have no idea where to look to figure out what happened. It might be nice to add a few || die statements in case anyone else runs into this, but when I retried (with --buildpkgonly, of course) I didn't have this problem a second time.