[gtk] combo box: Use standard padding

[Matthias Clasen <matthiasc src gnome org>]

commit 23f55f1c248c8d47e4ee7765c95796e8f5d28d20
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun May 26 22:19:04 2019 -0400

    combo box: Use standard padding

 gtk/gtkcombobox.h | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
---
diff --git a/gtk/gtkcombobox.h b/gtk/gtkcombobox.h
index 978e46846d..8a306b66fa 100644
--- a/gtk/gtkcombobox.h
+++ b/gtk/gtkcombobox.h
@@ -63,10 +63,7 @@ struct _GtkComboBoxClass
 
   /*< private >*/
 
-  /* Padding for future expansion */
-  void (*_gtk_reserved1) (void);
-  void (*_gtk_reserved2) (void);
-  void (*_gtk_reserved3) (void);
+  gpointer padding[8];
 };