output: constify damage APIs

include/wlr/types/wlr_output.h

@@ -206,7 +206,7 @@ struct wlr_output {
 
 struct wlr_output_event_damage {
 	struct wlr_output *output;
-	pixman_region32_t *damage; // output-buffer-local coordinates
+	const pixman_region32_t *damage; // output-buffer-local coordinates
 };
 
 struct wlr_output_event_precommit {
@@ -421,7 +421,7 @@ uint32_t wlr_output_preferred_read_format(struct wlr_output *output);
  * than what changed since last frame since multiple render buffers are used.
  */
 void wlr_output_set_damage(struct wlr_output *output,
-	pixman_region32_t *damage);
+	const pixman_region32_t *damage);
 /**
  * Test whether the pending output state would be accepted by the backend. If
  * this function returns true, wlr_output_commit() can only fail due to a
@@ -492,7 +492,7 @@ void wlr_output_lock_software_cursors(struct wlr_output *output, bool lock);
  * compositors render.
  */
 void wlr_output_render_software_cursors(struct wlr_output *output,
-	pixman_region32_t *damage);
+	const pixman_region32_t *damage);
 /**
  * Get the set of DRM formats suitable for the primary buffer, assuming a
  * buffer with the specified capabilities.

types/output/cursor.c

@@ -129,7 +129,7 @@ surface_damage_finish:
 }
 
 void wlr_output_render_software_cursors(struct wlr_output *output,
-		pixman_region32_t *damage) {
+		const pixman_region32_t *damage) {
 	int width, height;
 	wlr_output_transformed_resolution(output, &width, &height);
 

types/output/output.c

@@ -481,7 +481,7 @@ static void output_state_clear_buffer(struct wlr_output_state *state) {
 }
 
 void wlr_output_set_damage(struct wlr_output *output,
-		pixman_region32_t *damage) {
+		const pixman_region32_t *damage) {
 	pixman_region32_intersect_rect(&output->pending.damage, damage,
 		0, 0, output->width, output->height);
 	output->pending.committed |= WLR_OUTPUT_STATE_DAMAGE;