-#if defined(HB_MUTEX_IMPL_INIT) \
- && defined(hb_mutex_impl_init) \
- && defined(hb_mutex_impl_lock) \
- && defined(hb_mutex_impl_unlock) \
- && defined(hb_mutex_impl_finish)
-
-/* Defined externally, i.e. in config.h; must have typedef'ed hb_mutex_impl_t as well. */