gnutls_credentials_set(session->sess, GNUTLS_CRD_CERTIFICATE, x509_cred);
gnutls_certificate_server_set_request(session->sess, GNUTLS_CERT_REQUEST); // Request client certificate if any.
gnutls_dh_set_prime_bits(session->sess, dh_bits);
gnutls_credentials_set(session->sess, GNUTLS_CRD_CERTIFICATE, x509_cred);
gnutls_certificate_server_set_request(session->sess, GNUTLS_CERT_REQUEST); // Request client certificate if any.
gnutls_dh_set_prime_bits(session->sess, dh_bits);