[libdazzle] tree-builder: mark padding as private

[Christian Hergert <chergert src gnome org>]

commit 441f1047583f8a4f9fffa064447fb484a871f9da
Author: Christian Hergert <chergert redhat com>
Date:   Sat Dec 2 15:06:48 2017 -0800

    tree-builder: mark padding as private

 src/tree/dzl-tree-builder.h |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/tree/dzl-tree-builder.h b/src/tree/dzl-tree-builder.h
index 7f3e821..ae573cf 100644
--- a/src/tree/dzl-tree-builder.h
+++ b/src/tree/dzl-tree-builder.h
@@ -52,7 +52,8 @@ struct _DzlTreeBuilderClass
   void     (*node_collapsed)  (DzlTreeBuilder *builder,
                                DzlTreeNode    *node);
 
-  gpointer padding[12];
+  /*< private >*/
+  gpointer _padding[12];
 };
 
 DZL_AVAILABLE_IN_ALL