There is no reason to use Xsettings for the X11 backend, as it comes
from the GSetting store anyway, so move the font setting reading to
ClutterSettings and read directly from GSettings.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1364
Window scaling is a clutter feature used to enable automatic scaling of
stage windows when running under as an application in windowing system.
Clutter in mutter does not support running as a stand-alone application
toolkit, so lets remove this unused feature.
https://bugzilla.gnome.org/show_bug.cgi?id=777732
In cogl use cogl-config.h and in clutter use clutter-build-config.h. We
can't use clutter-config.h in clutter because its already used and
installed.
https://bugzilla.gnome.org/show_bug.cgi?id=768976
