diff --git a/gdk/quartz/gdkinputprivate.h b/gdk/quartz/gdkinputprivate.h
index 0868f33..7ba4293 100644
--- a/gdk/quartz/gdkinputprivate.h
+++ b/gdk/quartz/gdkinputprivate.h
@@ -34,7 +34,6 @@
 
 typedef struct _GdkAxisInfo    GdkAxisInfo;
 typedef struct _GdkInputVTable GdkInputVTable;
-typedef struct _GdkDevicePrivate GdkDevicePrivate;
 
 struct _GdkInputVTable {
   gint (*set_mode) (guint32 deviceid, GdkInputMode mode);
