Remove extern crate statements (#3310)

src/platform/ios.rs

@@ -283,7 +283,7 @@ pub enum Idiom {
     CarPlay,
 }
 
-bitflags! {
+bitflags::bitflags! {
     /// The [edges] of a screen.
     ///
     /// [edges]: https://developer.apple.com/documentation/uikit/uirectedge?language=objc

src/platform/macos.rs

@@ -2,6 +2,8 @@ use std::os::raw::c_void;
 
 use icrate::Foundation::MainThreadMarker;
 use objc2::rc::Id;
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 
 use crate::{
     event_loop::{EventLoopBuilder, EventLoopWindowTarget},