Map SO_EXCLUSIVEADDRUSE to !SO_REUSEADDR

	This will make windows app that use that property work on *nix.
	Fixes bug #643475.

mono/metadata/socket-io.c

@@ -1782,8 +1782,18 @@ void ves_icall_System_Net_Sockets_Socket_GetSocketOption_obj_internal(SOCKET soc
 
 	*error = 0;
 	
-	ret=convert_sockopt_level_and_name(level, name, &system_level,
-					   &system_name);
+#if !defined(SO_EXCLUSIVEADDRUSE) && defined(SO_REUSEADDR)
+	if (level == SocketOptionLevel_Socket && name == SocketOptionName_ExclusiveAddressUse) {
+		system_level = SOL_SOCKET;
+		system_name = SO_REUSEADDR;
+		ret = 0;
+	} else
+#endif
+	{
+
+		ret = convert_sockopt_level_and_name (level, name, &system_level, &system_name);
+	}
+
 	if(ret==-1) {
 		*error = WSAENOPROTOOPT;
 		return;
@@ -1890,9 +1900,12 @@ void ves_icall_System_Net_Sockets_Socket_GetSocketOption_obj_internal(SOCKET soc
 #endif
 
 	default:
+#if !defined(SO_EXCLUSIVEADDRUSE) && defined(SO_REUSEADDR)
+		if (level == SocketOptionLevel_Socket && name == SocketOptionName_ExclusiveAddressUse)
+			val = val ? 0 : 1;
+#endif
 		obj = int_to_object (domain, val);
 	}
-
 	*obj_val=obj;
 }
 
@@ -2007,6 +2020,15 @@ void ves_icall_System_Net_Sockets_Socket_SetSocketOption_internal(SOCKET sock, g
 
 	ret=convert_sockopt_level_and_name(level, name, &system_level,
 					   &system_name);
+
+#if !defined(SO_EXCLUSIVEADDRUSE) && defined(SO_REUSEADDR)
+	if (level == SocketOptionLevel_Socket && name == SocketOptionName_ExclusiveAddressUse) {
+		system_name = SO_REUSEADDR;
+		int_val = int_val ? 0 : 1;
+		ret = 0;
+	}
+#endif
+
 	if(ret==-1) {
 		*error = WSAENOPROTOOPT;
 		return;