compositor: let the shells create the screenshooter

desktop-shell/shell.c

@@ -6030,6 +6030,8 @@ module_init(struct weston_compositor *ec,
 		create_keyboard_focus_listener(seat);
 	}
 
+	screenshooter_create(ec);
+
 	shell_add_bindings(ec, shell);
 
 	shell_fade_init(shell);

src/compositor.c

@@ -3672,7 +3672,6 @@ weston_compositor_init(struct weston_compositor *ec,
 	if (weston_compositor_xkb_init(ec, &xkb_names) < 0)
 		return -1;
 
-	screenshooter_create(ec);
 	text_backend_init(ec);
 
 	wl_data_device_manager_init(ec->wl_display);

src/screenshooter.c

@@ -585,7 +585,7 @@ screenshooter_destroy(struct wl_listener *listener, void *data)
 	free(shooter);
 }
 
-void
+WL_EXPORT void
 screenshooter_create(struct weston_compositor *ec)
 {
 	struct screenshooter *shooter;