Revert Merge x-updates into master due to mesa bloat

See #490 discussion.

This reverts commit 1278859d31, reversing
changes made to 0c020c98f9.

Conflicts:
	pkgs/desktops/xfce/core/xfce4-session.nix (take master)
	pkgs/lib/misc.nix (auto)

pkgs/development/libraries/atk/default.nix

@@ -1,36 +0,0 @@
-{ stdenv, fetchurl, pkgconfig, perl, glib }:
-
-stdenv.mkDerivation rec {
-  name = "atk-2.8.0";
-
-  src = fetchurl {
-    url = "mirror://gnome/sources/atk/2.8/${name}.tar.xz";
-    sha256 = "1x3dd3hg9l1j9dq70xwph13vxdp6a9wbfcnryryf1wr6c8bij9dj";
-  };
-
-  nativeBuildInputs = [ pkgconfig perl ];
-
-  propagatedBuildInputs = [ glib ];
-
-  postInstall = "rm -rf $out/share/gtk-doc";
-
-  meta = {
-    description = "ATK, the accessibility toolkit";
-
-    longDescription = ''
-      ATK is the Accessibility Toolkit.  It provides a set of generic
-      interfaces allowing accessibility technologies such as screen
-      readers to interact with a graphical user interface.  Using the
-      ATK interfaces, accessibility tools have full access to view and
-      control running applications.
-    '';
-
-    homepage = http://library.gnome.org/devel/atk/;
-
-    license = "LGPLv2+";
-
-    maintainers = with stdenv.lib.maintainers; [ raskin urkud ];
-    platforms = stdenv.lib.platforms.linux;
-  };
-
-}