l9p_ingroup
match = l9p_ingroup(st->st_gid, gid, gids, ngids);
match = l9p_ingroup(tid, gid, gids, ngids);
else if (l9p_ingroup(st->st_gid, gid, gids, ngids))
static bool l9p_ingroup(gid_t tid, gid_t gid, gid_t *gids, size_t ngids);