--- htmlcxx-0.84/html/tree.h.orig	2005-02-22 05:47:04.000000000 +0100
+++ htmlcxx-0.84/html/tree.h	2014-09-09 12:27:17.170260318 +0200
@@ -50,6 +50,7 @@
 #include <stdexcept>
 #include <iterator>
 #include <set>
+#include <cstddef>
 
 // HP-style construct/destroy have gone from the standard,
 // so here is a copy.