remove wxWindow::m_needParent and use GTKNeedsParent() which can be overridden in just wxMenuBar (and not set in each and every wxGTK control)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@45602 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/menu.h

@@ -40,6 +40,10 @@ public:
     void SetLayoutDirection(wxLayoutDirection dir);
     wxLayoutDirection GetLayoutDirection() const;
 
+    // wxMenuBar is not a top level window but it still doesn't need a parent
+    // window
+    virtual bool GTKNeedsParent() const { return false; }
+
     void Attach(wxFrame *frame);
 
     // implementation only from now on