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.
gnome28 was a mix of packages from various releases, so do not mention 2.28 in the attribute name. svn path=/nixpkgs/trunk/; revision=29721