[gtk] text mark: Use standard padding

[Matthias Clasen <matthiasc src gnome org>]

commit f111e3f46755b8f023c5c637ebaa0764cde5da55
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon May 27 22:31:10 2019 +0000

    text mark: Use standard padding

 gtk/gtktextmark.h | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)
---
diff --git a/gtk/gtktextmark.h b/gtk/gtktextmark.h
index f9d3edb57e..c4d5fd4172 100644
--- a/gtk/gtktextmark.h
+++ b/gtk/gtktextmark.h
@@ -78,11 +78,9 @@ struct _GtkTextMarkClass
 {
   GObjectClass parent_class;
 
-  /* Padding for future expansion */
-  void (*_gtk_reserved1) (void);
-  void (*_gtk_reserved2) (void);
-  void (*_gtk_reserved3) (void);
-  void (*_gtk_reserved4) (void);
+  /*< private >*/
+
+  gpointer padding[8];
 };
 
 GDK_AVAILABLE_IN_ALL