Upstream changes to the build system required adjusting many packages'
dependencies. On the Nixpkgs side, we no longer propagate the dependency
on cmake (to reduce closure size), so downstream dependencies had to be
adjusted for most packages that depend on kdelibs.
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.
