egui-winit: don't call set_cursor each frame on any platform

On some platforms (WSL?) the setting of the cursor can also fail,
leading to warnings being logged by winit each frame. Not good.

crates/egui-winit/src/lib.rs

@@ -654,8 +654,8 @@ impl State {
     }
 
     fn set_cursor_icon(&mut self, window: &winit::window::Window, cursor_icon: egui::CursorIcon) {
-        // prevent flickering near frame boundary when Windows OS tries to control cursor icon for window resizing
-        #[cfg(windows)]
+        // Prevent flickering near frame boundary when Windows OS tries to control cursor icon for window resizing.
+        // On other platforms: just early-out to save CPU.
         if self.current_cursor_icon == cursor_icon {
             return;
         }