From 902217df2411129a4d26549fddd65002b433f762 Mon Sep 17 00:00:00 2001
From: John Maddock <john@johnmaddock.co.uk>
Date: Thu, 13 Jan 2011 12:14:56 +0000
Subject: [PATCH] Don't try and redefine macros that are already set.

[SVN r68095]
---
 include/boost/type_traits/common_type.hpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/boost/type_traits/common_type.hpp b/include/boost/type_traits/common_type.hpp
index 74b0363..25c877f 100644
--- a/include/boost/type_traits/common_type.hpp
+++ b/include/boost/type_traits/common_type.hpp
@@ -11,20 +11,20 @@
 
 #include <boost/config.hpp>
 
-#ifdef __SUNPRO_CC
+#if defined(__SUNPRO_CC) && !defined(BOOST_COMMON_TYPE_DONT_USE_TYPEOF)
 #  define BOOST_COMMON_TYPE_DONT_USE_TYPEOF
 #endif
-#ifdef __IBMCPP__
+#if defined(__IBMCPP__) && !defined(BOOST_COMMON_TYPE_DONT_USE_TYPEOF)
 #  define BOOST_COMMON_TYPE_DONT_USE_TYPEOF
 #endif
 
 //----------------------------------------------------------------------------//
-#if defined(BOOST_NO_VARIADIC_TEMPLATES)
+#if defined(BOOST_NO_VARIADIC_TEMPLATES) && !defined(BOOST_COMMON_TYPE_ARITY)
 #define BOOST_COMMON_TYPE_ARITY 3
 #endif
 
 //----------------------------------------------------------------------------//
-#if defined(BOOST_NO_DECLTYPE) && !defined(BOOST_COMMON_TYPE_DONT_USE_TYPEOF)
+#if defined(BOOST_NO_DECLTYPE) && !defined(BOOST_COMMON_TYPE_DONT_USE_TYPEOF) && !defined(BOOST_TYPEOF_SILENT)
 #define BOOST_TYPEOF_SILENT
 #include <boost/typeof/typeof.hpp>   // boost wonders never cease!
 #endif