Qt: fix RTL layout

Fix #9170

Qt doesn't set application layout direction by default, so we make it
use locale text direction, e.g. RTL for Arabic.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/qt4.cpp

@@ -479,6 +479,10 @@ static void *Thread( void *obj )
     /* Start the QApplication here */
     QVLCApp app( argc, argv );
 
+    /* Set application direction to locale direction,
+     * necessary for  RTL locales */
+    app.setLayoutDirection(QLocale().textDirection());
+
     p_intf->p_sys->p_app = &app;