Make Perl 5.20 the default Perl
glibc/2.19 -> glibc

We only have one version of Glibc so no need for a separate directory.
Remove tabs/whitespace
busybox: Remove unused patch
Rename badly named linuxHeaders_3_7 (it's actually 3.12)
Remove obsolete useDietLibC stdenv adapter
Remove obsolete useKlibc stdenv adapter
curl: Remove static link support

We only needed this for the stdenv bootstrap, but not anymore.
busybox: Enable building a minimal configuration

This starts with "make allnoconfig" rather than "make defconfig",
making it easier to turn on only the needed features.

Also, fix broken .config generation (the presence of "#" lines
confused parseconfig).
busybox: Allow running from within the Nix store

This enables running the busybox program directly from the Nix store
(i.e. as /nix/store/<hash>-busybox). We need this for the stdenv
bootstrap.
Update the stdenv bootstrap tools generator

The static curl program is gone, replaced by curl inside of the
bootstrap tools tarball. Also, we generate a .tar.xz archive rather
than .cpio.bz2, making the download smaller. The separate
{sh,cpio,mkdir,ln,bzip2} programs have been replaced by a single
busybox program.
uclibc: Fix building against recent kernel headers
busybox: Optionally use uclibc
uclibc: Update to the latest prerelease

This resolves a segfault in busybox.
Update the stdenv-linux bootstrap tools
glibc: Update to 2.20
aterm: Fix building on Glibc 2.20
grub2: Fix building against Glibc 2.20

http://hydra.nixos.org/build/16563301
imagemagick: Use --with-gcc-arch

Without this, ImageMagick's configure script will generate code
specific to the machine building the package. This code may then fail
on other CPU types.

http://hydra.nixos.org/build/16564129
xorg.xf86-video-vmware: fix build against glibc-2.20