window: Don't crash if a cursor image failed to load.

Signed-off-by: Dima Ryazanov <dima@gmail.com>

clients/window.c

@@ -687,10 +687,14 @@ create_cursors(struct display *display)
 	display->cursor_shm_pool = shm_pool_create(display, pool_size);
 
 	for (i = 0; i < count; i++) {
-		if (!images[i])
+		cursor = &display->cursors[i];
+
+		if (!images[i]) {
+			cursor->n_images = 0;
+			cursor->images = NULL;
 			continue;
+		}
 
-		cursor = &display->cursors[i];
 		create_cursor_from_images(display, cursor, images[i]);
 
 		XcursorImagesDestroy(images[i]);
@@ -1958,6 +1962,9 @@ input_set_pointer_image(struct input *input, uint32_t time, int pointer)
 	if (pointer == input->current_cursor)
 		return;
 
+	if (display->cursors[pointer].n_images == 0)
+		return;
+
 	image = &display->cursors[pointer].images[0];
 
 	if (!image->surface)