Don't use lower-case Qt macros

ffmpeglauncher.h

@@ -21,7 +21,7 @@ public:
     void setTargetDir(const QString &path);
     void setTargetExtension(const QString &extension);
 
-private slots:
+private Q_SLOTS:
     void nextSong();
     void stopFfmpeg();
     void ffmpegStarted();

playerwatcher.h

@@ -40,7 +40,7 @@ signals:
     void playbackStarted();
     void playbackStopped();
 
-private slots:
+private Q_SLOTS:
     void serviceOwnerChanged(const QString &service, const QString &oldOwner, const QString &newOwner);
     void propertiesChanged();
     void notificationReceived();