ui: compile out some qemu-pixman functions when !PIXMAN Those functions require the PIXMAN library. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>