If the rectangle is allocate a size smaller than the border, drawing the
border will end up with negative coordinates, and will mess up the whole
thing. Since rectangles don't have a minimum preferred size, we cannot
rely on the allocation being big enough to contain the border and the
background color.
If the rectangle is smaller than the border width value, we just paint
the border color as well.
Cogl 1.16 has deprecated a lot of API which it will be difficult for
Clutter to catch up with. For the time being the warnings are just
being disabled to keep the build output clean.
https://bugzilla.gnome.org/show_bug.cgi?id=703877
We cannot fully deprecate Geometry, because ClutterActor and ClutterText
are actually using the type in signals and properties; but we can
deprecate the API that uses this type, so that 2.0 will be able to avoid
it entirely.