Update smithay, with xwayland shell, Cow, etc.

src/wayland/handlers/xwayland_shell.rs

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-3.0-only
+
+use crate::state::State;
+use smithay::{
+    delegate_xwayland_shell,
+    wayland::xwayland_shell::{XWaylandShellHandler, XWaylandShellState},
+};
+
+impl XWaylandShellHandler for State {
+    fn xwayland_shell_state(&mut self) -> &mut XWaylandShellState {
+        &mut self.common.xwayland_shell_state
+    }
+}
+
+delegate_xwayland_shell!(State);