--- boost/config/compiler/vacpp.hpp.orig	2012-03-21 13:32:36.000000000 -0400
+++ boost/config/compiler/vacpp.hpp	2012-05-08 14:59:24.000000000 -0400
@@ -78,7 +78,9 @@
 #  define BOOST_NO_CHAR16_T
 #  define BOOST_NO_CHAR32_T
 #endif
-#define BOOST_NO_CONSTEXPR
+#if ! __IBMCPP_CONSTEXPR
+#  define BOOST_NO_CONSTEXPR
+#endif
 #if ! __IBMCPP_DECLTYPE
 #  define BOOST_NO_DECLTYPE
 #else
@@ -87,7 +89,9 @@
 #define BOOST_NO_DECLTYPE_N3276
 #define BOOST_NO_DEFAULTED_FUNCTIONS
 #define BOOST_NO_DELETED_FUNCTIONS
-#define BOOST_NO_EXPLICIT_CONVERSION_OPERATORS
+#if ! __IBMCPP_EXPLICIT_CONVERSION_OPERATORS
+#  define BOOST_NO_EXPLICIT_CONVERSION_OPERATORS
+#endif
 #if ! __IBMCPP_EXTERN_TEMPLATE
 #  define BOOST_NO_EXTERN_TEMPLATE
 #endif
@@ -101,8 +105,12 @@
 #define BOOST_NO_NOEXCEPT
 #define BOOST_NO_NULLPTR
 #define BOOST_NO_RAW_LITERALS
-#define BOOST_NO_RVALUE_REFERENCES
-#define BOOST_NO_SCOPED_ENUMS
+#if ! __IBMCPP_RVALUE_REFERENCES
+#  define BOOST_NO_RVALUE_REFERENCES
+#endif
+#if ! __IBMCPP_SCOPED_ENUM
+#  define BOOST_NO_SCOPED_ENUMS
+#endif
 #define BOOST_NO_SFINAE_EXPR
 #define BOOST_NO_UNIFIED_INITIALIZATION_SYNTAX
 #if ! __IBMCPP_STATIC_ASSERT