Properly set WM_CLASS atom even if Display pointer was passed to TQApplication

This relates to Bug 1443
(cherry picked from commit e154d27e30)

src/kernel/qapplication.cpp

@@ -320,6 +320,7 @@ void qt_init( int *, char **, QApplication::Type );
 void qt_cleanup();
 #if defined(Q_WS_X11)
 void qt_init( Display* dpy, Qt::HANDLE, Qt::HANDLE );
+void qt_init( int *, char **, Display* dpy, Qt::HANDLE, Qt::HANDLE );
 #endif
 Q_EXPORT bool qt_tryModalHelper( QWidget *widget, QWidget **rettop );
 
@@ -908,7 +909,7 @@ QApplication::QApplication(Display *dpy, int argc, char **argv,
 
 	qt_init( &argc, argv, GuiClient );
     } else {
-	qt_init(dpy, visual, colormap);
+	qt_init( &argc, argv, dpy, visual, colormap );
     }
 
     process_cmdline( &argc, argv );

src/kernel/qapplication_x11.cpp

@@ -1639,7 +1639,7 @@ void qt_init_internal( int *argcptr, char **argv,
     }
 #endif
 
-    if ( display ) {
+    if ( display && ((!argcptr) || (!argv)) ) {
 	// Qt part of other application
 
 	appForeignDpy = TRUE;
@@ -2439,6 +2439,11 @@ void qt_init( Display *display, Qt::HANDLE visual, Qt::HANDLE colormap )
     qt_init_internal( 0, 0, display, visual, colormap );
 }
 
+void qt_init( int *argcptr, char **argv, Display *display, Qt::HANDLE visual, Qt::HANDLE colormap )
+{
+    qt_init_internal( argcptr, argv, display, visual, colormap );
+}
+
 
 /*****************************************************************************
   qt_cleanup() - cleans up when the application is finished