don't use annoying and unneeded in C++ casts of NULL to "T *" in all other files neither

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@58227 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/x11/window.h

@@ -73,13 +73,13 @@ public:
     virtual int GetCharWidth() const;
     virtual void GetTextExtent(const wxString& string,
         int *x, int *y,
-        int *descent = (int *) NULL,
-        int *externalLeading = (int *) NULL,
+        int *descent = NULL,
+        int *externalLeading = NULL,
         const wxFont *theFont = (const wxFont *) NULL)
         const;
 
     virtual void ScrollWindow( int dx, int dy,
-        const wxRect* rect = (wxRect *) NULL );
+        const wxRect* rect = NULL );
 
 #if wxUSE_DRAG_AND_DROP
     virtual void SetDropTarget( wxDropTarget *dropTarget );