This is all work of Marc Weber <marco-oweber@gmx.de>, except for a few nitpicks.
Tested space blowup: IMHO negligible to headers and similar stuff,
e.g. the firefox closure (reported by du) grows from 560 to 579 MB.
Saving space should be handled separately,
e.g. we have the multiple-outputs branch.
See #490 discussion.
This reverts commit 1278859d3167b9f84bfab680d9c8c463adf64a60, reversing
changes made to 0c020c98f9d4f49d5c9907db5f4b35aac7df959b.
Conflicts:
pkgs/desktops/xfce/core/xfce4-session.nix (take master)
pkgs/lib/misc.nix (auto)
x-updates is supposed to merge after stdenv-updates, so let's test it
Conflicts:
pkgs/development/libraries/gtk+/2.x.nix (both updated, taking newer)
pkgs/development/libraries/mesa/default.nix (taking nativeBuildInputs)