Revert "GameActivity PATCH: remove unused variable"

This reverts commit 73d56ed.

Author: jb55

android-activity/game-activity-csrc/game-activity/native_app_glue/android_native_app_glue.c

@@ -399,6 +399,7 @@ static void onSaveInstanceState(GameActivity* activity,
     LOGV("SaveInstanceState: %p", activity);
 
     struct android_app* android_app = ToApp(activity);
+    void* savedState = NULL;
     pthread_mutex_lock(&android_app->mutex);
     android_app->stateSaved = 0;
     android_app_write_cmd(android_app, APP_CMD_SAVE_STATE);