Add parenthesis in while (packet = socket->Recv ()) to make clang++ (LLVM) happy

src/internet/examples/main-simple.cc

@@ -25,7 +25,7 @@ static void
 SocketPrinter (Ptr<Socket> socket)
 {
   Ptr<Packet> packet;
-  while (packet = socket->Recv ())
+  while ((packet = socket->Recv ()))
     { 
       std::cout << "at=" << Simulator::Now ().GetSeconds () << "s, rx bytes=" << packet->GetSize () << std::endl;
     }