Currently, Meta/Cogl/Clutter makes use of cairo_rectangle_int_t despite
the existance of MetaRectangle.
In order to make MetaRectangle usable in Cogl/Clutter as well, Mtk would
provide such base types that are shared across the various private
libraries
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3128>