diff --git a/include/boost/phoenix/config.hpp b/include/boost/phoenix/config.hpp
index 9f2138c8..ad81c019 100644
--- a/include/boost/phoenix/config.hpp
+++ b/include/boost/phoenix/config.hpp
@@ -2,6 +2,7 @@
     Copyright (c) 2001-2010 Joel de Guzman
     Copyright (c) 2010      Eric Niebler
     Copyright (c) 2014-2015 John Fletcher
+    Copyright (c) 2016      Kohei Takahashi
 
     Distributed under the Boost Software License, Version 1.0. (See accompanying
     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -27,50 +28,43 @@
 // #endif
 //
 // #ifdef BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
-// #define BOOST_PHOENIX_UNORDERED_SET_HEADER <unordered_set>
-// #define BOOST_PHOENIX_UNORDERED_MAP_HEADER <unordered_map>
+// #include BOOST_PHOENIX_UNORDERED_SET_HEADER
+// #include BOOST_PHOENIX_UNORDERED_MAP_HEADER
 // #endif
 //
 // The client code can then chose the implementation provided.
 // See the example in test/stl/querying_find2.cpp
-//
-//////////////////////////////////////////////////////////////////////////
-//
+
 // There is no specific thing in Boost Config for libc++
 #ifdef _LIBCPP_VERSION
 #define BOOST_PHOENIX_USING_LIBCPP
+#endif
+
 // This may not be true for some very old version of libc++
 // Current libc++ supports unordered_set and unordered_map without C++11.
-#undef BOOST_NO_CXX11_HDR_UNORDERED_MAP
-#undef BOOST_NO_CXX11_HDR_UNORDERED_SET
+#if defined(BOOST_PHOENIX_USING_LIBCPP) \
+ && !(defined(BOOST_NO_CXX11_HDR_UNORDERED_MAP) || defined(BOOST_NO_CXX11_HDR_UNORDERED_SET))
+// This is either libc++ or C++11 or later
+#define BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
+#define BOOST_PHOENIX_UNORDERED_SET_HEADER <unordered_set>
+#define BOOST_PHOENIX_UNORDERED_MAP_HEADER <unordered_map>
+#define BOOST_PHOENIX_UNORDERED_NAMESPACE std
 #endif
 
-#if (!defined(BOOST_PHOENIX_USING_LIBCPP) \
-  && (defined (BOOST_NO_CXX11_HDR_UNORDERED_MAP) || \
-     defined (BOOST_NO_CXX11_HDR_UNORDERED_SET) ) )
-#ifdef BOOST_HAS_HASH
+#if defined(BOOST_HAS_HASH)
 // This is to sort out case of Clang when using stdlib from gcc
 // as Clang thinks it is gcc 4.2.1
 // This prevents the failure to include a header with a warning.
 #define _GLIBCXX_PERMIT_BACKWARD_HASH
-#define BOOST_PHOENIX_PERMIT_BACKWARD_HASH
 #define BOOST_PHOENIX_HASH_SET_HEADER BOOST_HASH_SET_HEADER
 #define BOOST_PHOENIX_HASH_MAP_HEADER BOOST_HASH_MAP_HEADER
 #define BOOST_PHOENIX_HAS_HASH
 #define BOOST_PHOENIX_HASH_NAMESPACE BOOST_STD_EXTENSION_NAMESPACE
-
 #elif defined(BOOST_DINKUMWARE_STDLIB) && (BOOST_DINKUMWARE_STDLIB < 610)
 #define BOOST_PHOENIX_HASH_SET_HEADER <hash_set>
 #define BOOST_PHOENIX_HASH_MAP_HEADER <hash_map>
 #define BOOST_PHOENIX_HAS_HASH
 #define BOOST_PHOENIX_HASH_NAMESPACE stdext
 #endif
-#else
-// This is either libc++ or C++11 or later
-#define BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
-#define BOOST_PHOENIX_UNORDERED_SET_HEADER <unordered_set>
-#define BOOST_PHOENIX_UNORDERED_MAP_HEADER <unordered_map>
-#define BOOST_PHOENIX_UNORDERED_NAMESPACE std
-#endif
 
 #endif
diff --git a/include/boost/phoenix/stl/algorithm/detail/std_unordered_set_or_map_fwd.hpp b/include/boost/phoenix/stl/algorithm/detail/std_unordered_set_or_map_fwd.hpp
index 2e1a8436..e650328d 100644
--- a/include/boost/phoenix/stl/algorithm/detail/std_unordered_set_or_map_fwd.hpp
+++ b/include/boost/phoenix/stl/algorithm/detail/std_unordered_set_or_map_fwd.hpp
@@ -23,8 +23,8 @@
 #if defined(BOOST_PHOENIX_USING_LIBCPP) \
   || (defined(BOOST_DINKUMWARE_STDLIB) && (BOOST_DINKUMWARE_STDLIB < 540))
 // Advance declaration not working for libc++ and MSVC 10
-#include <unordered_set>
-#include <unordered_map>
+#include BOOST_PHOENIX_UNORDERED_SET_HEADER
+#include BOOST_PHOENIX_UNORDERED_MAP_HEADER
 #else
 
 
diff --git a/test/algorithm/querying.cpp b/test/algorithm/querying.cpp
index 2ab97c63..fd9b9124 100644
--- a/test/algorithm/querying.cpp
+++ b/test/algorithm/querying.cpp
@@ -15,17 +15,10 @@
 
 #include <boost/config.hpp>
 
-#ifdef BOOST_HAS_HASH
+#ifdef BOOST_PHOENIX_HAS_HASH
 #define _GLIBCXX_PERMIT_BACKWARD_HASH
 #include BOOST_HASH_SET_HEADER
 #include BOOST_HASH_MAP_HEADER
-#define BOOST_PHOENIX_HAS_HASH
-#define BOOST_PHOENIX_HASH_NAMESPACE BOOST_STD_EXTENSION_NAMESPACE
-#elif defined(BOOST_DINKUMWARE_STDLIB) && (BOOST_DINKUMWARE_STDLIB < 610)
-#include <hash_set>
-#include <hash_map>
-#define BOOST_PHOENIX_HAS_HASH
-#define BOOST_PHOENIX_HASH_NAMESPACE stdext
 #endif
 
 #include <set>
diff --git a/test/algorithm/querying_find.cpp b/test/algorithm/querying_find.cpp
index 976a1070..99707aa2 100644
--- a/test/algorithm/querying_find.cpp
+++ b/test/algorithm/querying_find.cpp
@@ -15,29 +15,13 @@
 
 #include <boost/config.hpp>
 
-#if defined(BOOST_DINKUMWARE_STDLIB) && (BOOST_DINKUMWARE_STDLIB < 610)
-#include <hash_set>
-#include <hash_map>
-#define BOOST_PHOENIX_HAS_HASH
-#define BOOST_PHOENIX_HASH_NAMESPACE stdext
-#else
-#if (defined (BOOST_NO_CXX11_HDR_UNORDERED_MAP) || \
-     defined (BOOST_NO_CXX11_HDR_UNORDERED_SET) )
-#ifdef BOOST_HAS_HASH
-// This does not work for Clang when using stdlib from gcc 4.9
-// as Clang thinks it is gcc 4.2.1
-//#ifndef BOOST_COMP_CLANG
-#define _GLIBCXX_PERMIT_BACKWARD_HASH
-#include BOOST_HASH_SET_HEADER
-#include BOOST_HASH_MAP_HEADER
-#define BOOST_PHOENIX_HAS_HASH
-#define BOOST_PHOENIX_HASH_NAMESPACE BOOST_STD_EXTENSION_NAMESPACE
-#endif
-#else
-#define BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
-#include <unordered_set>
-#include <unordered_map>
+#ifdef BOOST_PHOENIX_HAS_HASH
+#include BOOST_PHOENIX_HASH_SET_HEADER
+#include BOOST_PHOENIX_HASH_MAP_HEADER
 #endif
+#ifdef BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
+#include BOOST_PHOENIX_UNORDERED_SET_HEADER
+#include BOOST_PHOENIX_UNORDERED_MAP_HEADER
 #endif
 
 #include <set>
@@ -89,7 +73,9 @@ namespace
         convert_to_container<BOOST_PHOENIX_HASH_NAMESPACE::hash_map<int, int> >();
         BOOST_TEST(boost::phoenix::find(arg1, 2)(hm) == hm.find(2));
 
-#elif defined BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
+#endif
+#ifdef BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
+
         std::unordered_set<int> us(array, array + 3);
         BOOST_TEST(boost::phoenix::find(arg1, 2)(us) == us.find(2));
 
diff --git a/test/algorithm/querying_find2.cpp b/test/algorithm/querying_find2.cpp
index f1ee475f..9f6b8c54 100644
--- a/test/algorithm/querying_find2.cpp
+++ b/test/algorithm/querying_find2.cpp
@@ -22,17 +22,12 @@
 #ifdef BOOST_PHOENIX_HAS_HASH
 #include BOOST_PHOENIX_HASH_SET_HEADER
 #include BOOST_PHOENIX_HASH_MAP_HEADER
-#elif defined(BOOST_DINKUMWARE_STDLIB) && (BOOST_DINKUMWARE_STDLIB < 610)
-#include <hash_set>
-#include <hash_map>
-#define BOOST_PHOENIX_HAS_HASH
-#define BOOST_PHOENIX_HASH_NAMESPACE stdext
-#elif defined BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
+#endif
+#ifdef BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
 #include BOOST_PHOENIX_UNORDERED_SET_HEADER
 #include BOOST_PHOENIX_UNORDERED_MAP_HEADER
 #endif
 
-
 namespace
 {
     struct even
@@ -76,7 +71,8 @@ namespace
         convert_to_container<BOOST_PHOENIX_HASH_NAMESPACE::hash_map<int, int> >();
         BOOST_TEST(boost::phoenix::find(arg1, 2)(hm) == hm.find(2));
 
-#elif defined BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
+#endif
+#ifdef BOOST_PHOENIX_HAS_UNORDERED_SET_AND_MAP
 
         std::unordered_set<int> us(array, array + 3);
         BOOST_TEST(boost::phoenix::find(arg1, 2)(us) == us.find(2));