Update SCTK to 0.18.0

The update is pretty minor, however we support now
`WindowEvent::Occluded` when xdg-shell v6 is available.

It also adds support for `Window::show_window_menu`.

Fixes #2927.

src/platform_impl/linux/x11/mod.rs

@@ -32,7 +32,7 @@ use std::{
     ops::Deref,
     os::{
         raw::*,
-        unix::io::{AsRawFd, RawFd},
+        unix::io::{AsRawFd, BorrowedFd},
     },
     ptr,
     rc::Rc,
@@ -82,7 +82,7 @@ use crate::{
 const ALL_DEVICES: u16 = 0;
 const ALL_MASTER_DEVICES: u16 = 1;
 
-type X11Source = Generic<RawFd>;
+type X11Source = Generic<BorrowedFd<'static>>;
 
 struct WakeSender<T> {
     sender: Sender<T>,
@@ -268,7 +268,8 @@ impl<T: 'static> EventLoop<T> {
 
         // Create the X11 event dispatcher.
         let source = X11Source::new(
-            xconn.xcb_connection().as_raw_fd(),
+            // SAFETY: xcb owns the FD and outlives the source.
+            unsafe { BorrowedFd::borrow_raw(xconn.xcb_connection().as_raw_fd()) },
             calloop::Interest::READ,
             calloop::Mode::Level,
         );

src/platform_impl/linux/x11/window.rs

@@ -1636,6 +1636,9 @@ impl UnownedWindow {
         self.drag_initiate(util::MOVERESIZE_MOVE)
     }
 
+    #[inline]
+    pub fn show_window_menu(&self, _position: Position) {}
+
     /// Resizes the window while it is being dragged.
     pub fn drag_resize_window(&self, direction: ResizeDirection) -> Result<(), ExternalError> {
         self.drag_initiate(match direction {