Sometimes the build failes with:
In file included from ../../gcc-4.4.6/gcc/ada/seh_init.c:44:
../../gcc-4.4.6/gcc/system.h:418: error: conflicting types for 'strsignal'
/nix/store/6h129q168ahnl2nzw6azr239cba884ng-glibc-2.18/include/string.h:560: note: previous declaration of 'strsignal' was here
and sometimes it doesn't. Hopefully disabling parallel builds fixes
this.
http://hydra.nixos.org/build/7179481
This is for consistency with terminology in stdenv (and the terms
"hostDrv" and "buildDrv" are not very intuitive, even if they're
consistent with GNU terminology).