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/sha1.cc
--- src/sha1.cc.orig
+++ src/sha1.cc
@@ -22,10 +22,10 @@
   #include <botan/benchmark.h>
 #endif
 
-#include "sanity.hh"
-#include "ui.hh"
 #include "platform.hh"
 #include "cmd.hh"
+#include "sanity.hh"
+#include "ui.hh"
 #include "transforms.hh"
 
 using std::string;