[gtk/master.msvc] gtkpopoveraccessible.c: Fix build on Visual Studio

[Chun-wei Fan <fanchunwei src gnome org>]

commit 31264ef81da4082772b8cb82dc514a709db58a3c
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Thu Mar 12 11:47:11 2020 +0800

    gtkpopoveraccessible.c: Fix build on Visual Studio
    
    Visual Studio does not allow empty structures, unfortunately

 gtk/a11y/gtkpopoveraccessible.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gtk/a11y/gtkpopoveraccessible.c b/gtk/a11y/gtkpopoveraccessible.c
index 6e73a34a47..6cdeb8aade 100644
--- a/gtk/a11y/gtkpopoveraccessible.c
+++ b/gtk/a11y/gtkpopoveraccessible.c
@@ -27,6 +27,7 @@ typedef struct _GtkPopoverAccessiblePrivate GtkPopoverAccessiblePrivate;
 
 struct _GtkPopoverAccessiblePrivate
 {
+  gchar dummy;
 };
 
 G_DEFINE_TYPE_WITH_CODE (GtkPopoverAccessible, gtk_popover_accessible, GTK_TYPE_CONTAINER_ACCESSIBLE,