kcdsa_compute_pub_from_priv
ret = kcdsa_compute_pub_from_priv(&pub, priv); EG(ret, err);
ret = kcdsa_compute_pub_from_priv(&pub2, &priv); EG(ret, err);
ATTRIBUTE_WARN_UNUSED_RET int kcdsa_compute_pub_from_priv(kcdsa_pub_key *pub,