This doesn't actually help, but maybe is "correct"...? Or quite possibly not.

src/libtomahawk/album.h

@@ -38,7 +38,7 @@ public:
     static album_ptr get( unsigned int id, const QString& name, const Tomahawk::artist_ptr& artist );
 
     Album( unsigned int id, const QString& name, const Tomahawk::artist_ptr& artist );
-    ~Album();
+    virtual ~Album();
 
     unsigned int id() const { return m_id; }
     QString name() const { return m_name; }

src/libtomahawk/playlist.h

@@ -132,7 +132,7 @@ friend class ::DatabaseCommand_CreatePlaylist;
 friend class DynamicPlaylist;
 
 public:
-    ~Playlist();
+    virtual ~Playlist();
 
     static Tomahawk::playlist_ptr load( const QString& guid );
 

src/libtomahawk/playlist/albumproxymodel.h

@@ -32,6 +32,7 @@ Q_OBJECT
 
 public:
     explicit AlbumProxyModel( QObject* parent = 0 );
+    virtual ~AlbumProxyModel() {}
 
     virtual AlbumModel* sourceModel() const { return m_model; }
     virtual void setSourceAlbumModel( AlbumModel* sourceModel );

src/libtomahawk/playlist/playlistproxymodel.h

@@ -29,6 +29,7 @@ Q_OBJECT
 
 public:
     explicit PlaylistProxyModel( QObject* parent = 0 );
+    virtual ~PlaylistProxyModel() {}
 };
 
 #endif // PLAYLISTPROXYMODEL_H

src/libtomahawk/playlist/playlistview.h

@@ -31,7 +31,7 @@ Q_OBJECT
 
 public:
     explicit PlaylistView( QWidget* parent = 0 );
-    ~PlaylistView();
+    virtual ~PlaylistView();
 
     PlaylistModel* playlistModel() const { return m_model; }
     virtual void setPlaylistModel( PlaylistModel* model );

src/libtomahawk/playlist/trackproxymodel.h

@@ -32,6 +32,7 @@ Q_OBJECT
 
 public:
     explicit TrackProxyModel ( QObject* parent = 0 );
+    virtual ~TrackProxyModel() {}
     
     virtual TrackModel* sourceModel() const { return m_model; }
     virtual void setSourceTrackModel( TrackModel* sourceModel );

src/libtomahawk/playlist/treeproxymodel.h

@@ -34,6 +34,7 @@ Q_OBJECT
 
 public:
     explicit TreeProxyModel( QObject* parent = 0 );
+    virtual ~TreeProxyModel() {}
 
     virtual TreeModel* sourceModel() const { return m_model; }
     virtual void setSourceTreeModel( TreeModel* sourceModel );

src/libtomahawk/sourceplaylistinterface.h

@@ -36,7 +36,7 @@ Q_OBJECT
 
 public:
     SourcePlaylistInterface( Tomahawk::source_ptr& source );
-    ~SourcePlaylistInterface();
+    virtual ~SourcePlaylistInterface();
 
     QList<Tomahawk::query_ptr> tracks();
 

src/libtomahawk/viewmanager.h

@@ -70,7 +70,7 @@ public:
     static ViewManager* instance();
 
     explicit ViewManager( QObject* parent = 0 );
-    ~ViewManager();
+    virtual ~ViewManager();
 
     QWidget* widget() const { return m_widget; }
     InfoBar* infobar() const { return m_infobar; }

src/libtomahawk/widgets/welcomewidget.h

@@ -81,7 +81,7 @@ Q_OBJECT
 
 public:
     WelcomeWidget( QWidget* parent = 0 );
-    ~WelcomeWidget();
+    virtual ~WelcomeWidget();
 
     virtual QWidget* widget() { return this; }
     virtual Tomahawk::playlistinterface_ptr playlistInterface() const;