if both the GLES and EGL libs and headers are found.
Fold all the includes and libraries into 1 varaible each and use those.
in other words, you need to have both OpenGLES and EGL to do a successful build.
All OpenGL related files are build as a kwinglutils library for OpenGL
and as a kwinglesutils library for OpenGL ES. The appropriate defines
are set using target_properties and removed from kwinconfig.h.cmake.
Second part of cleaning up the lib directory: the effects library
now lives in libkwineffects/ directory.
For existing effects nothing changes as the install path is unchanged.
The change obsoletes the lib/ directory.
As glplatform.h has not yet been exported I dared to export it and
adjust the places where it is used.
CCMAIL: kwin@kde.org
