Add the Qt window module as an alternative to the SDL2 module

Att the Qt window module as an alternative to the SDL2 module

Description is TBD

src/module/qt_window/mainwindow.cc

@@ -8,7 +8,7 @@ MainWindow::MainWindow(struct module_qt_window_s *qt_window, QWidget *parent)
     setCentralWidget(qt_window->mpv_widget);
     setFocusPolicy(Qt::StrongFocus);
 
-    connect(this, &MainWindow::emitCloseMpv, this, &MainWindow::__closeMpv, Qt::QueuedConnection);
+    connect(this, &MainWindow::emitCloseMpv, this, &MainWindow::__closeMpv, Qt::BlockingQueuedConnection);
 }
 
 void MainWindow::closeMpv(bool* exited) noexcept {