A function macro named E clashes with internal boost definitions.  Rearrange
the order of header inclusion so that affected boost headers are included
before monotone defines the macro.

Also, stop bundling boost/circular_buffer, which is available in current
versions of boost. From Fedora.

Index: src/charset.cc
--- src/charset.cc.orig
+++ src/charset.cc
@@ -7,12 +7,12 @@
 // implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 // PURPOSE.
 
-#include "base.hh"
-#include "vector.hh"
-
 #include <boost/tokenizer.hpp>
 #include <idna.h>
 #include <stringprep.h>
+
+#include "base.hh"
+#include "vector.hh"
 
 #include "charset.hh"
 #include "numeric_vocab.hh"