ossl_dh_key_todata
int ossl_dh_key_todata(DH *dh, OSSL_PARAM_BLD *bld, OSSL_PARAM params[],
ok = ok && ossl_dh_key_todata(dh, tmpl, NULL, include_private);
&& ossl_dh_key_todata(dh, NULL, params, 1);