This incorporates the following two commits from <nixpkgs>:
NixOS/nixpkgs@f83af95f8aNixOS/nixpkgs@5e7a1cf955
Hydra was the original reason why I was fixing tempdir creation in the
first place. Seeing that Hydra ships its own versions of these scripts,
we need to patch them here as well.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>