Add display pref for macOS.

zero-ui-view/src/gl.rs

@@ -142,6 +142,10 @@ impl GlContextManager {
         ))]
         let display_pref = DisplayApiPreference::GlxThenEgl(Box::new(winit::platform::x11::register_xlib_error_hook));
 
+        #[cfg(target_os = "macos")]
+        let display_pref = DisplayApiPreference::Cgl;
+        
+
         // SAFETY: we are trusting the `raw_display_handle` from winit here.
         let display = unsafe { Display::new(display_handle, display_pref) }?;