diff --git a/include/boost/mpl/aux_/config/compiler.hpp b/include/boost/mpl/aux_/config/compiler.hpp
index 26052dc..35417c3 100644
--- a/include/boost/mpl/aux_/config/compiler.hpp
+++ b/include/boost/mpl/aux_/config/compiler.hpp
@@ -21,21 +21,19 @@
 #include "boost/config.hpp"
 
 #if defined(BOOST_MSVC) && BOOST_MSVC < 1300
-#   define BOOST_MPL_COMPILER_CLASS msvc60
+#   define BOOST_MPL_COMPILER_DIR msvc60
 #elif defined(BOOST_MSVC) && BOOST_MSVC == 1300
-#   define BOOST_MPL_COMPILER_CLASS msvc70
+#   define BOOST_MPL_COMPILER_DIR msvc70
 #elif defined(__GNUC__)
-#   define BOOST_MPL_COMPILER_CLASS gcc
+#   define BOOST_MPL_COMPILER_DIR gcc
 #elif defined(__BORLANDC__)
-#   define BOOST_MPL_COMPILER_CLASS bcc
+#   define BOOST_MPL_COMPILER_DIR bcc
 #elif defined(__MWERKS__) && __MWERKS__ <= 0x3001
-#   define BOOST_MPL_COMPILER_CLASS mwcw
+#   define BOOST_MPL_COMPILER_DIR mwcw
 #elif defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
-#   define BOOST_MPL_COMPILER_CLASS no_ctps
+#   define BOOST_MPL_COMPILER_DIR no_ctps
 #else
-#   define BOOST_MPL_COMPILER_CLASS plain
+#   define BOOST_MPL_COMPILER_DIR plain
 #endif
 
-#define BOOST_MPL_COMPILER_DIR BOOST_MPL_COMPILER_CLASS/
-
 #endif // BOOST_MPL_AUX_CONFIG_COMPILER_HPP_INCLUDED
diff --git a/include/boost/mpl/aux_/include_preprocessed.hpp b/include/boost/mpl/aux_/include_preprocessed.hpp
index a179fed..cfc917a 100644
--- a/include/boost/mpl/aux_/include_preprocessed.hpp
+++ b/include/boost/mpl/aux_/include_preprocessed.hpp
@@ -20,20 +20,11 @@
 #include "boost/preprocessor/cat.hpp"
 #include "boost/preprocessor/stringize.hpp"
 
-// local macro, #undef-ined at the end of the header
-#define AUX_PREPROCESSED_HEADER \
-    BOOST_PP_STRINGIZE( \
-        BOOST_PP_CAT( \
-              BOOST_PP_CAT( \
-                  boost/mpl/aux_/preprocessed/ \
-                , BOOST_MPL_COMPILER_DIR \
-                ) \
-            , BOOST_MPL_PREPROCESSED_HEADER \
-            ) \
-        ) \
+#   define AUX_PREPROCESSED_HEADER \
+    aux_/preprocessed/BOOST_MPL_COMPILER_DIR/BOOST_MPL_PREPROCESSED_HEADER \
 /**/
 
-#include AUX_PREPROCESSED_HEADER
+#   include BOOST_PP_STRINGIZE(boost/mpl/AUX_PREPROCESSED_HEADER)
+#   undef AUX_PREPROCESSED_HEADER
 
-#undef AUX_PREPROCESSED_HEADER
 #undef BOOST_MPL_PREPROCESSED_HEADER