fix windows code to build with MSVC

- remove __attribute__((unused)) not supported on MSVC
- remove  __attribute((unused)) not supported on MSVC
- add symbol exports to RemoteDataReadQueue and RemoteDataQueue
- add export symbols to sdrsrv

plugins/samplesink/hackrfoutput/hackrfoutputplugin.cpp

@@ -123,9 +123,9 @@ PluginInterface::SamplingDevices HackRFOutputPlugin::enumSampleSinks()
 
 #ifdef SERVER_MODE
 PluginInstanceGUI* HackRFOutputPlugin::createSampleSinkPluginInstanceGUI(
-        const QString& sinkId __attribute__((unused)),
-        QWidget **widget __attribute__((unused)),
-        DeviceUISet *deviceUISet __attribute__((unused)))
+        const QString& sinkId,
+        QWidget **widget,
+        DeviceUISet *deviceUISet)
 {
     return 0;
 }