Index: codecvt_null.cpp
===================================================================
--- codecvt_null.cpp	(revision 39562)
+++ codecvt_null.cpp	(working copy)
@@ -7,6 +7,7 @@
 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt)
 
+#define BOOST_ARCHIVE_SOURCE
 #include <boost/archive/codecvt_null.hpp>
 
 // codecvt implementation for passing wchar_t objects to char output