[gtk] treepopover: Fix header guard

[Matthias Clasen <matthiasc src gnome org>]

commit 69fa15981c1c8f44ea285c7928a89450cd842d83
Author: Timm Bäder <mail baedert org>
Date:   Wed Feb 5 16:11:28 2020 +0100

    treepopover: Fix header guard

 gtk/gtktreepopoverprivate.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtktreepopoverprivate.h b/gtk/gtktreepopoverprivate.h
index a43bfcb15f..2656f90a1d 100644
--- a/gtk/gtktreepopoverprivate.h
+++ b/gtk/gtktreepopoverprivate.h
@@ -17,7 +17,7 @@
  * Author: Matthias Clasen
  */
 
-#ifndef __GTK_TREE_POPOPVER_PRIVATE_H__
+#ifndef __GTK_TREE_POPOVER_PRIVATE_H__
 #define __GTK_TREE_POPOVER_PRIVATE_H__
 
 #include <gtk/gtk.h>