[Linux] Fix a rendering problem

The backend should always use logical size
[Linux] Handle expose event correctly

The expose events before last one should be ignored, the erea they
exposed should be added to the dirty area for later rendering.
[Linux] Free host_window in DestoryNotify

This should be more rebost, in case the Window is not destroyed by
OS_Close_Window for whatever reason
[Linux] Code for clipping box debugging
[Linux] Correct debugging output
[Makefile] Fix broken symbolic link
[Linux] Disable debugging info