Compile fix for Window name

src/ui/MainWindow.cc

@@ -509,12 +509,12 @@ void MainWindow::configureWindowName()
 {
     QList<QHostAddress> hostAddresses = QNetworkInterface::allAddresses();
     QString windowname = qApp->applicationName() + " " + qApp->applicationVersion();
-    bool prevAddr = false;
 
     // XXX we do have UDP MAVLink heartbeat broadcast now in SITL and will have it on the
     // WIFI radio, so people should not be in need any more of knowing their IP.
     // this can go once we are certain its not needed any more.
     #if 0
+    bool prevAddr = false;
     windowname.append(" (" + QHostInfo::localHostName() + ": ");
     for (int i = 0; i < hostAddresses.size(); i++)
     {