Merge remote-tracking branch 'upstream/master' into x-updates

Conflicts:
	pkgs/development/libraries/cairo/default.nix
	pkgs/development/libraries/gdk-pixbuf/default.nix
	pkgs/development/libraries/gtk+/2.x.nix
	pkgs/misc/ghostscript/default.nix
	pkgs/top-level/all-packages.nix