On X11, fix errors bleeding from hooks handling them

This commit fixes it, by not updating the `latest_error` when
any of the hooks handled the error, otherwise it'd interfere
with the winit's error checking.

src/platform_impl/linux/mod.rs

@@ -653,9 +653,9 @@ unsafe extern "C" fn x_error_callback(
         // Don't log error.
         if !error_handled {
             error!("X11 error: {:#?}", error);
+            // XXX only update the error, if it wasn't handled by any of the hooks.
+            *xconn.latest_error.lock().unwrap() = Some(error);
         }
-
-        *xconn.latest_error.lock().unwrap() = Some(error);
     }
     // Fun fact: this return value is completely ignored.
     0