chore: cleanup platform specific code

runtime/src/window.rs

@@ -222,7 +222,7 @@ pub fn frames() -> Subscription<(Id, Instant)> {
         _ => None,
     })
 }
-#[cfg(feature = "wayland")]
+#[cfg(all(feature = "cctk", target_os = "linux"))]
 /// Subscribes to the frames of the window of the running application.
 ///
 /// The resulting [`Subscription`] will produce items at a rate equal to the