The type has been deprecated, so stop using it. The easiest replacement
would be to add our own struct, but considering that separate name/value
arrays are easier to free (g_auto!) and we already do the split in one
place, go that route.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/689
GList's used in legacy code were free'd using a g_list_foreach + g_list_free,
while we can just use g_list_free_full as per GLib 2.28.
So replace code where we were using this legacy codepath.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/576
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
