When adding a subsurface (to display a tooltip) in toytoolkit,
we now get the parent window surface type (SHM or EGL) and
define the new surface type as the same.
This fixes crashes with tooltips in cases like having
Cairo-EGL available but running the X11 compositor.
Signed-off-by: Manuel Bachmann <manuel.bachmann@open.eurogiciel.org>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>