ThreadSocketHandler2(): cast to avoid signed/unsigned warning

src/net.cpp

@@ -621,7 +621,7 @@ void ThreadSocketHandler2(void* parg)
         if (nSelect == SOCKET_ERROR)
         {
             int nErr = WSAGetLastError();
-            if (hSocketMax > -1)
+            if (hSocketMax > (SOCKET) -1)
             {
                 printf("socket select error %d\n", nErr);
                 for (unsigned int i = 0; i <= hSocketMax; i++)