diff -Naur liborigin-20080225.orig/tree.hh liborigin-20080225/tree.hh
--- liborigin-20080225.orig/tree.hh	2008-02-25 11:19:47.000000000 +0100
+++ liborigin-20080225/tree.hh	2011-07-01 13:32:16.702486023 +0200
@@ -61,6 +61,7 @@
 #define tree_hh_
 
 #include <cassert>
+#include <cstddef>
 #include <memory>
 #include <stdexcept>
 #include <iterator>