glibc: pull a bug work-around from Arch (i686-only ATM)

This should work around some of our build problems,
e.g. http://hydra.nixos.org/build/7575893/nixlog/1/tail-reload

I tested the builds of jdk and xbmc were broken on my build machine, and now they work. It's a stdenv change for i686, but to me it seems worth it.

If noone protests, I plan to merge in about a day or two? (I don't see any Hydra branch suitable for pre-building this, for nixos:glibc-2.18 is stopped.)