Fix Qt crash on exit

modules/gui/qt4/dialogs/playlist.hpp

@@ -39,6 +39,7 @@ public:
         if( !instance) instance = new PlaylistDialog( p_intf );
         return instance;
     }
+    static void killInstance() { if( instance ) delete instance; }
     virtual ~PlaylistDialog();
 private:
 

modules/gui/qt4/dialogs_provider.cpp

@@ -52,6 +52,11 @@ DialogsProvider::DialogsProvider( intf_thread_t *_p_intf ) :
              this, menuUpdateAction( QObject *) );
 }
 
+DialogsProvider::~DialogsProvider()
+{
+    PlaylistDialog::killInstance();
+}
+
 void DialogsProvider::customEvent( QEvent *event )
 {
     if( event->type() == DialogEvent_Type )

modules/gui/qt4/dialogs_provider.hpp

@@ -52,7 +52,8 @@ public:
             instance = new DialogsProvider( p_intf );
         return instance;
     }
-    virtual ~DialogsProvider() {};
+    static void killInstance() { if( instance ) delete instance; }
+    virtual ~DialogsProvider();
     QTimer *fixed_timer;
 protected:
     friend class QVLCMenu;

modules/gui/qt4/main_interface.cpp

@@ -276,6 +276,8 @@ void MainInterface::updateOnTimer()
 {
     if( p_intf->b_die )
     {
+        QApplication::closeAllWindows();
+        DialogsProvider::killInstance();
         QApplication::quit();
     }
     audio_volume_t i_volume;

modules/gui/qt4/qt4.cpp

@@ -145,7 +145,6 @@ static void Init( intf_thread_t *p_intf )
 
     app->setQuitOnLastWindowClosed( false );
     app->exec();
- //   fprintf( stderr, "Qt execution terminated\n" );
     MainInputManager::killInstance();
     delete p_intf->p_sys->p_mi;
 }