_krb5_n_fold
ret = _krb5_n_fold(constant, len, k, et->blocksize);
ret = _krb5_n_fold(c, len, k, res_len);
_krb5_n_fold (
ret = _krb5_n_fold (t->str, strlen(t->str), data, t->n);
ret = _krb5_n_fold(str, len, tmp, 24);
ret = _krb5_n_fold(str, len, tmp, keylen);