This macro was introduced so as to be able to be built without GLib.
However, this feature was long ago removed, and in Mutter we depend on
it anyway, so let's get rid of it in favor of more consistency.
Move the KMS interaction from cogl into mutter, where most of the other
KMS interaction already takes place. This also removes dead code which
were only excercised when non-mutter callers used the cogl KMS backend.
The cogl KMS API was updated to pass via MetaRendererNative instead of
via the different cogl objects.
https://bugzilla.gnome.org/show_bug.cgi?id=768976
