xlibs: replace occurrences by xorg

This seems to have been confusing people, using both xlibs and xorg, etc.
- Avoided renaming local (and different) xlibs binding in gcc*.
- Fixed cases where both xorg and xlibs were used.
Hopefully everything still works as before.

pkgs/applications/editors/lighttable/default.nix

@@ -1,14 +1,14 @@
 { stdenv, fetchurl, buildEnv, makeDesktopItem, makeWrapper, zlib, glib, alsaLib
 , dbus, gtk, atk, pango, freetype, fontconfig, libgnome_keyring3, gdk_pixbuf
-, cairo, cups, expat, libgpgerror, nspr, gnome3, nss, xlibs, udev
+, cairo, cups, expat, libgpgerror, nspr, gnome3, nss, xorg, udev
 }:
 
 let
   libPath = stdenv.lib.makeLibraryPath [
       stdenv.cc.cc zlib glib dbus gtk atk pango freetype libgnome_keyring3 nss
       fontconfig gdk_pixbuf cairo cups expat libgpgerror alsaLib nspr gnome3.gconf
-      xlibs.libXrender xlibs.libX11 xlibs.libXext xlibs.libXdamage xlibs.libXtst
-      xlibs.libXcomposite xlibs.libXi xlibs.libXfixes
+      xorg.libXrender xorg.libX11 xorg.libXext xorg.libXdamage xorg.libXtst
+      xorg.libXcomposite xorg.libXi xorg.libXfixes
 ];
 in
 assert stdenv.system == "i686-linux" || stdenv.system == "x86_64-linux";