`g_object_notify()` actually takes a global lock to look up the property
by its name, which means there is a performance hit (albeit tiny) every
time this function is called. For this reason, always try to use
`g_object_notify_by_pspec()` instead.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/703
Glib stopped providing any fallback implementations on systems without
memmove() all the way back in 2013. Since then, the symbol is a simple
macro around memmove(); use that function directly now that glib added
a deprecation warning.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/689
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