diff -ruN zipios++-0.1.5.9+cvs.2007.04.28.orig/src/directory.h zipios++-0.1.5.9+cvs.2007.04.28/src/directory.h
--- zipios++-0.1.5.9+cvs.2007.04.28.orig/src/directory.h	2003-01-04 06:45:34.000000000 +0800
+++ zipios++-0.1.5.9+cvs.2007.04.28/src/directory.h	2012-01-24 22:30:20.362767134 +0800
@@ -56,6 +56,8 @@
 
 namespace boost
 {
+        using std::ptrdiff_t;
+
 	namespace filesystem
 	{
 		class dir_it;