Add Multicast capabilities for LAN server scanning.

code/qcommon/qcommon.h

@@ -138,6 +138,7 @@ typedef enum {
 	NA_BROADCAST,
 	NA_IP,
 	NA_IP6,
+	NA_MULTICAST6,
 	NA_UNSPEC
 } netadrtype_t;
 
@@ -172,6 +173,8 @@ const char	*NET_AdrToString (netadr_t a);
 const char      *NET_AdrToStringwPort (netadr_t a);
 qboolean	NET_StringToAdr ( const char *s, netadr_t *a, netadrtype_t family);
 qboolean	NET_GetLoopPacket (netsrc_t sock, netadr_t *net_from, msg_t *net_message);
+void		NET_JoinMulticast6(void);
+void		NET_LeaveMulticast6(void);
 void		NET_Sleep(int msec);