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

Signed-off-by: Dima Ryazanov <dima@gmail.com>
diff --git a/clients/window.c b/clients/window.c
index 2c59b23..72d36d3 100644
--- a/clients/window.c
+++ b/clients/window.c
@@ -687,10 +687,14 @@
 	display->cursor_shm_pool = shm_pool_create(display, pool_size);
 
 	for (i = 0; i < count; i++) {
-		if (!images[i])
-			continue;
-
 		cursor = &display->cursors[i];
+
+		if (!images[i]) {
+			cursor->n_images = 0;
+			cursor->images = NULL;
+			continue;
+		}
+
 		create_cursor_from_images(display, cursor, images[i]);
 
 		XcursorImagesDestroy(images[i]);
@@ -1958,6 +1962,9 @@
 	if (pointer == input->current_cursor)
 		return;
 
+	if (display->cursors[pointer].n_images == 0)
+		return;
+
 	image = &display->cursors[pointer].images[0];
 
 	if (!image->surface)