k5_size_authdata
k5_size_authdata(krb5_authdata *authdata, size_t *sizep);
kret = k5_size_authdata(ctx->authdata[i], &required);
if (!k5_size_authdata(authdata, &required) && required <= remain) {
kret = k5_size_authdata(authenticator->authorization_data[i],