Adopt the FindGLIB2.cmake from kdelibs.
Adopt the FindGLIB2.cmake from kdelibs.

BUG: 247546

KDE/phonon-quicktime,shadeslayer/phonon-gstreamer,KDE/phonon-directshow,KDE/phonon-gstreamer,KDE/phonon-xine,KDE/phonon-waveout,shadeslayer/phonon-gstreamer,KDE/phonon-gstreamer,shadeslayer/phonon-gstreamer,KDE/phonon-mmf,KDE/phonon-xine,KDE/phonon-directshow,KDE/phonon-xine