nghttpx: Guard TLS1_3_VERSION

src/shrpx_tls.cc

@@ -560,11 +560,13 @@ int ticket_key_cb(SSL *ssl, unsigned char *key_name, unsigned char *iv,
                nullptr);
   EVP_DecryptInit_ex(ctx, key.cipher, nullptr, key.data.enc_key.data(), iv);
 
+#ifdef TLS1_3_VERSION
   // If ticket_key_cb is not set, OpenSSL always renew ticket for
   // TLSv1.3.
   if (SSL_version(ssl) == TLS1_3_VERSION) {
     return 2;
   }
+#endif // TLS1_3_VERSION
 
   return i == 0 ? 1 : 2;
 }