MetaGravity is an enum, where the values match the X11 macros used for
gravity, with the exception that `ForgetGravity` was renamed
`META_GRAVITY_NONE` to have less of a obscure name.
The motivation for this is to rely less on libX11 data types and macros
in generic code.
https://gitlab.gnome.org/GNOME/mutter/merge_requests/705
GList's used in legacy code were free'd using a g_slist_foreach + g_slist_free,
while we can just use g_slist_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
The order and way include macros were structured was chaotic, with no
real common thread between files. Try to tidy up the mess with some
common scheme, to make things look less messy.
testboxes was a binary that did unit testing, but it wasn't integrated
to the test system, so in effect, it was never run. Instead integrate it
into the other mutter unit tests. This includes changing a few of
meta_warning()s into g_warning()s so that the GTest framework can handle
them.
