XCB: Use application name for X11 selection owner name

This makes it possible for clipboard managers (or other scripts) to
distinguish different Qt applications and act differently.

Change-Id: I5bc5a1914b51127b24a81142ca9dbdb196ffd0d8
Fixes: QTBUG-72806
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>

src/plugins/platforms/xcb/qxcbconnection.cpp

@@ -39,6 +39,7 @@
 
 #include <QtGui/private/qguiapplication_p.h>
 #include <QtCore/QDebug>
+#include <QtCore/QCoreApplication>
 
 #include "qxcbconnection.h"
 #include "qxcbkeyboard.h"
@@ -817,7 +818,7 @@ xcb_window_t QXcbConnection::getQtSelectionOwner()
                           0);                                 // value list
 
         QXcbWindow::setWindowTitle(connection(), m_qtSelectionOwner,
-                               QStringLiteral("Qt Selection Window"));
+                                   QLatin1String("Qt Selection Owner for ") + QCoreApplication::applicationName());
     }
     return m_qtSelectionOwner;
 }