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/basic_io.hh
--- src/basic_io.hh.orig
+++ src/basic_io.hh
@@ -11,11 +11,11 @@
 #ifndef __BASIC_IO_HH__
 #define __BASIC_IO_HH__
 
-#include "vector.hh"
 #include <map>
 
 #include "paths.hh"
 #include "sanity.hh"
+#include "vector.hh"
 #include "vocab.hh"
 #include "numeric_vocab.hh"
 #include "char_classifiers.hh"