first include to have the UA_ENABLE_DISCOVERY definition

src/server/ua_server_discovery.c

@@ -2,12 +2,12 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#ifdef UA_ENABLE_DISCOVERY
-
 #include "ua_server_internal.h"
 #include "ua_client.h"
 #include "ua_config_standard.h"
 
+#ifdef UA_ENABLE_DISCOVERY
+
 static UA_StatusCode
 register_server_with_discovery_server(UA_Server *server, const char* discoveryServerUrl,
                                       const UA_Boolean isUnregister,