Port NCMD_EXIT to i_net file

src/common/engine/i_net.cpp

@@ -117,6 +117,8 @@ static SOCKET mysocket = INVALID_SOCKET;
 static sockaddr_in sendaddress[MAXNETNODES];
 static uint8_t sendplayer[MAXNETNODES];
 
+constexpr int NET_EXIT = 0x80;
+
 #ifdef __WIN32__
 const char *neterror (void);
 #else
@@ -306,7 +308,7 @@ void PacketGet (void)
 					GetPlayerName(node).GetChars());
 			}
 
-			doomcom.data[0] = NCMD_EXIT;
+			doomcom.data[0] = NET_EXIT;
 			c = 1;
 		}
 		else if (err != WSAEWOULDBLOCK)
@@ -345,7 +347,7 @@ void PacketGet (void)
 	else if (c > 0)
 	{	//The packet is not from any in-game node, so we might as well discard it.
 		// Don't show the message for disconnect notifications.
-		if (TransmitBuffer[0] != NCMD_EXIT)
+		if (TransmitBuffer[0] != NET_EXIT)
 		{
 			if (TransmitBuffer[0] != PRE_FAKE)
 				DPrintf(DMSG_WARNING, "Dropped packet: Unknown host (%s:%d)\n", inet_ntoa(fromaddress.sin_addr), fromaddress.sin_port);