NG_HOOK_SET_PRIVATE
#define NG_HOOK_SET_PRIVATE(hook, val) do {(hook)->private = val;} while (0)
#define NG_HOOK_SET_PRIVATE(hook, val) _ng_hook_set_private(hook, val, _NN_)
#define NG_HOOK_SET_PRIVATE(hook, val) _NG_HOOK_SET_PRIVATE(hook, val)