puffs_cred_hasgroup
} else if (puffs_cred_hasgroup(pcr, gid)) {
((newgroup != group && !puffs_cred_hasgroup(pcr, newgroup))))
if (!puffs_cred_hasgroup(pcr, group) && (mode & S_ISGID))
bool puffs_cred_hasgroup(const struct puffs_cred *, gid_t);