Windows: Changed thread_event_target_callback's WM_DESTROY to WM_NCDESTROY (#1780)

CHANGELOG.md

@@ -1,5 +1,6 @@
 # Unreleased
 
+- On Windows, fix applications not exiting gracefully due to thread_event_target_callback accessing corrupted memory.
 - On Windows, implement `Window::set_ime_position`.
 - **Breaking:** On Windows, Renamed `WindowBuilderExtWindows`'s `is_dark_mode` to `theme`.
 - On Windows, add `WindowBuilderExtWindows::with_theme` to set a preferred theme.

src/platform_impl/windows/event_loop.rs

@@ -1939,7 +1939,7 @@ unsafe extern "system" fn thread_event_target_callback<T: 'static>(
     // the closure to catch_unwind directly so that the match body indendation wouldn't change and
     // the git blame and history would be preserved.
     let callback = || match msg {
-        winuser::WM_DESTROY => {
+        winuser::WM_NCDESTROY => {
             Box::from_raw(subclass_input);
             drop(subclass_input);
             0