replace wm_destroy by wm_close

src/platform/windows/events_loop.rs

@@ -281,7 +281,7 @@ pub unsafe extern "system" fn callback(window: winapi::HWND, msg: winapi::UINT,
                                        -> winapi::LRESULT
 {
     match msg {
-        winapi::WM_DESTROY => {
+        winapi::WM_CLOSE => {
             use events::WindowEvent::Closed;
             send_event(Event::WindowEvent {
                 window_id: SuperWindowId(WindowId(window)),

src/platform/windows/window.rs

@@ -282,7 +282,7 @@ impl Drop for Window {
     #[inline]
     fn drop(&mut self) {
         unsafe {
-            user32::PostMessageW(self.window.0, winapi::WM_DESTROY, 0, 0);
+            user32::PostMessageW(self.window.0, winapi::WM_CLOSE, 0, 0);
         }
     }
 }