--- gd-2.0.36.orig/gd_io.h	2007-11-27 09:30:34.000000000 +0100
+++ gd-2.0.36/gd_io.h	2012-10-14 16:10:30.000000000 +0200
@@ -26,6 +26,7 @@ typedef struct gdIOCtx
 
   void (*gd_free) (struct gdIOCtx *);
 
+  void    *data;
 }
 gdIOCtx;