pixman-renderer: Replace output-create flags with struct

pixman_renderer_output_create currently takes a flags enum bitmask for
its options. Switch this to using a structure, so we can introduce other
non-boolean options.

Signed-off-by: Daniel Stone <daniels@collabora.com>

libweston/backend-wayland/wayland.c

@@ -799,8 +799,10 @@ cleanup_window:
 static int
 wayland_output_init_pixman_renderer(struct wayland_output *output)
 {
-	return pixman_renderer_output_create(&output->base,
-				     PIXMAN_RENDERER_OUTPUT_USE_SHADOW);
+	const struct pixman_renderer_output_options options = {
+		.use_shadow = true,
+	};
+	return pixman_renderer_output_create(&output->base, &options);
 }
 
 static void