static_cast<ThreadLocalValueHolderBase*>(pthread_getspecific(key_));
    if (holder != NULL) {
      return CheckedDowncastToActualType<ValueHolder>(holder)->pointer();
    }

    ValueHolder* const new_holder = new ValueHolder(default_);
    ThreadLocalValueHolderBase* const holder_base = new_holder;
    GTEST_CHECK_POSIX_SUCCESS_(pthread_setspecific(key_, holder_base));
    return new_holder->pointer();
  }

	// when a C thread exits after a cgo call.
	// We only invoke this function once per thread in runtime.needAndBindM,
	// and the next calls just reuse the bound m.
	pthread_setspecific(pthread_g, g);
}

void
x_cgo_notify_runtime_init_done(void* dummy __attribute__ ((unused))) {
	pthread_mutex_lock(&runtime_init_mu);
	__atomic_store_n(&runtime_init_done, 1, __ATOMIC_RELEASE);