Slightly reduce number of cfgs (#3071)

* Make Linux platforms less dependent on the root monitor handle

* Add various functions to the Wayland platform to reduce cfgs

* Don't use a cfg in listen_device_events

* Don't use a cfg in set_content_protected

* Fix instance of a target_os cfg

src/platform_impl/ios/event_loop.rs

@@ -22,7 +22,8 @@ use crate::{
     error::EventLoopError,
     event::Event,
     event_loop::{
-        ControlFlow, EventLoopClosed, EventLoopWindowTarget as RootEventLoopWindowTarget,
+        ControlFlow, DeviceEvents, EventLoopClosed,
+        EventLoopWindowTarget as RootEventLoopWindowTarget,
     },
     platform::ios::Idiom,
 };
@@ -45,6 +46,9 @@ impl<T: 'static> EventLoopWindowTarget<T> {
         Some(MonitorHandle::new(UIScreen::main(self.mtm)))
     }
 
+    #[inline]
+    pub fn listen_device_events(&self, _allowed: DeviceEvents) {}
+
     pub fn raw_display_handle(&self) -> RawDisplayHandle {
         RawDisplayHandle::UiKit(UiKitDisplayHandle::empty())
     }