X509_V_FLAG_CHECK_SS_SIGNATURE
X509_VERIFY_PARAM_set_flags(vpm, X509_V_FLAG_CHECK_SS_SIGNATURE);
X509_STORE_CTX_set_flags(xsc, X509_V_FLAG_CHECK_SS_SIGNATURE);
|| ((ctx->param->flags & X509_V_FLAG_CHECK_SS_SIGNATURE) != 0