Destroy a mutex created with SDL_CreateMutex().
void SDL_DestroyMutex(SDL_mutex * mutex);
the mutex to destroy
This function must be called on any mutex that is no longer needed. Failure to destroy a mutex will result in a system memory or resource leak. While it is safe to destroy a mutex that is _unlocked_, it is not safe to attempt to destroy a locked mutex, and may result in undefined behavior depending on the platform.
This function is available since SDL 2.0.0.