Clean X11/XCB detection
Review Request #125252 - Created Sept. 15, 2015 and updated
Put X11 and XCB at the same level outside APPLE if block.
That way if one wants to try building with X11 on OS X it possible.
Build on OS X 10.8
can you please ensure whether kwindowsystem can be built that way? There is the kkeyserver which has compile time switched classes and OSX and X11 are mutual exclusive. It might be that the build system for OSX is just broken and it doesn't build. But we should make sure that we don't introduce now a problem for when OSX gets the build system eventually fixed.