Fix compile warnings

src/core/mainwindow.cpp

@@ -2171,6 +2171,8 @@ void MainWindow::CopyFilesToDevice(const QList<QUrl> &urls) {
   else {
     QMessageBox::warning(this, tr("Error"), tr("None of the selected songs were suitable for copying to a device"));
   }
+#else
+  Q_UNUSED(urls);
 #endif
 }
 

src/core/qtsystemtrayicon.cpp

@@ -239,6 +239,8 @@ void QtSystemTrayIcon::SetVisible(bool visible) {
 void QtSystemTrayIcon::SetNowPlaying(const Song &song, const QUrl &cover_url) {
 
 #ifdef Q_OS_WIN
+  Q_UNUSED(song);
+  Q_UNUSED(cover_url);
   // Windows doesn't support HTML in tooltips, so just show something basic
   tray_->setToolTip(song.PrettyTitleWithArtist());
 #else

src/core/utilities.cpp

@@ -602,6 +602,7 @@ int SetThreadIOPriority(IoPriority priority) {
 #elif defined(Q_OS_MACOS)
   return setpriority(PRIO_DARWIN_THREAD, 0, priority == IOPRIO_CLASS_IDLE ? PRIO_DARWIN_BG : 0);
 #else
+  Q_UNUSED(priority);
   return 0;
 #endif
 

src/core/windows7thumbbar.cpp

@@ -136,10 +136,11 @@ void Windows7ThumbBar::HandleWinEvent(MSG *msg) {
     if (hr != S_OK)
       qLog(Debug) << "Failed to add buttons" << hex << DWORD (hr);
     for (int i = 0; i < actions_.count(); i++) {
-      if (buttons[i].hIcon > 0)
+      if (buttons[i].hIcon)
         DestroyIcon (buttons[i].hIcon);
     }
-  } else if (msg->message == WM_COMMAND) {
+  }
+  else if (msg->message == WM_COMMAND) {
     const int button_id = LOWORD(msg->wParam);
 
     if (button_id >= 0 && button_id < actions_.count()) {
@@ -164,7 +165,7 @@ void Windows7ThumbBar::ActionChanged() {
 
     button->iId = i;
     SetupButton(action, button);
-    if (buttons->hIcon > 0) DestroyIcon(buttons->hIcon);
+    if (buttons->hIcon) DestroyIcon(buttons->hIcon);
   }
 
   taskbar_list->ThumbBarUpdateButtons((HWND)widget_->winId(), actions_.count(), buttons);

src/engine/directsounddevicefinder.cpp

@@ -46,6 +46,8 @@ QList<DeviceFinder::Device> DirectSoundDeviceFinder::ListDevices() {
 
 BOOL DirectSoundDeviceFinder::EnumerateCallback(LPGUID guid, LPCSTR description, LPCSTR module, LPVOID state_voidptr) {
 
+  Q_UNUSED(module);
+
   State *state = reinterpret_cast<State*>(state_voidptr);
 
   Device dev;