Fix segfault if swaybg is run without Wayland

Mirrors a similar check in `swaylock/main.c`

1 files changed, 3 insertions, 1 deletions

diff --git a/swaybg/main.c b/swaybg/main.c
index 2fdd4220..3124ae3d 100644
--- a/swaybg/main.c
+++ b/swaybg/main.c
@@ -31,7 +31,9 @@ void sway_terminate(int exit_code) {
                 window_teardown(window);
         }
         list_free(surfaces);
-        registry_teardown(registry);
+        if (registry) {
+                registry_teardown(registry);
+        }
         exit(exit_code);
 }