Utils: Collapse most of porting,h

Taking the Qt 6 branches, leaving some dummies until downstream
adapted.

Change-Id: Ib9b86568d73c341c8f740ba497c3cbfab830d8a1
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/plugins/coreplugin/fancytabwidget.cpp

@@ -164,7 +164,7 @@ bool FancyTabBar::event(QEvent *event)
 }
 
 // Resets hover animation on mouse enter
-void FancyTabBar::enterEvent(EnterEvent *event)
+void FancyTabBar::enterEvent(QEnterEvent *event)
 {
     Q_UNUSED(event)
     m_hoverRect = QRect();