add prototypes for NET_FindURLInMemCache, NET_DisplayMemCacheInfoAsHTML, and NET_InitMemCacProtocol to reduce Mac compiler warnings

network/cache/mkmemcac.h

@@ -58,4 +58,11 @@ NET_FirstMemCacheObject(XP_List* list_ptr);
 extern net_CacheObject * 
 NET_NextMemCacheObject(XP_List* list_ptr);
 
+#ifndef NU_CACHE
+MODULE_PRIVATE int NET_FindURLInMemCache(URL_Struct * URL_s, MWContext *ctxt);
+MODULE_PRIVATE void NET_DisplayMemCacheInfoAsHTML(ActiveEntry * cur_entry);
+void NET_InitMemCacProtocol(void);
+
+#endif
+
 #endif /* MK_MEMORY_CACHE_H */