Due to changes in build system we have always either OpenGL or OpenGL ES.
This allows to remove the KWIN_HAVE_OPENGL_COMPOSITING define. In the
effects the define is kept as KWIN_HAVE_OPENGL which can be used in
future to build also an XRender only effect system.
Building the workspaces requires to have all the build dependencies
which were required for KWIN_HAVE_COMPOSITING to be set. This allows
us to remove all the ifdefs for this and gives us a cleaner code.
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
