diff -up lyx-2.0.0beta3/src/support/unicode.h.gcc46 lyx-2.0.0beta3/src/support/unicode.h
--- lyx-2.0.0beta3/src/support/unicode.h.gcc46	2010-03-11 00:50:43.000000000 -0600
+++ lyx-2.0.0beta3/src/support/unicode.h	2011-02-07 07:45:09.693198552 -0600
@@ -15,6 +15,7 @@
 
 #include "support/strfwd.h"
 
+#include <cstddef>
 #include <vector>