[gtk] toggle tool button: Use standard padding

[Matthias Clasen <matthiasc src gnome org>]

commit 5db4530a22be623deeea80ed37386c690b9e4e3d
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue May 28 18:58:31 2019 -0400

    toggle tool button: Use standard padding

 gtk/gtktoggletoolbutton.h | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)
---
diff --git a/gtk/gtktoggletoolbutton.h b/gtk/gtktoggletoolbutton.h
index 525f8514ce..bef39c613f 100644
--- a/gtk/gtktoggletoolbutton.h
+++ b/gtk/gtktoggletoolbutton.h
@@ -64,11 +64,7 @@ struct _GtkToggleToolButtonClass
 
   /*< private >*/
 
-  /* Padding for future expansion */
-  void (* _gtk_reserved1) (void);
-  void (* _gtk_reserved2) (void);
-  void (* _gtk_reserved3) (void);
-  void (* _gtk_reserved4) (void);
+  gpointer padding[8];
 };
 
 GDK_AVAILABLE_IN_ALL