(svn r6754) -Codechange: Remove some #idef ENABLE_NETWORK specific defines. With networking

disabled hardcode _networking/_network_available to zero and let the compiler
 handle all optimizations.

network_udp.h

@@ -14,6 +14,6 @@ NetworkGameList *NetworkUDPQueryServer(const char* host, unsigned short port);
 void NetworkUDPAdvertise(void);
 void NetworkUDPRemoveAdvertise(void);
 
-#endif
+#endif /* ENABLE_NETWORK */
 
 #endif /* NETWORK_UDP_H */