diff --git a/include/__config b/include/__config
index d8b0a99..bb4e72e 100644
--- a/include/__config
+++ b/include/__config
@@ -144,6 +144,10 @@
 #define _LIBCPP_HAS_NO_VARIADICS
 #endif
 
+#if !(__has_feature(cxx_trailing_return))
+#define _LIBCPP_HAS_NO_TRAILING_RETURN
+#endif
+
 #if __has_feature(cxx_inline_namespaces)
 #define _LIBCPP_BEGIN_NAMESPACE_STD namespace std {inline namespace _LIBCPP_NAMESPACE {
 #define _LIBCPP_END_NAMESPACE_STD  } }
@@ -190,6 +194,8 @@
 
 #else  // __GXX_EXPERIMENTAL_CXX0X__
 
+#define _LIBCPP_HAS_NO_TRAILING_RETURN
+
 #if !(__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
 #define _LIBCPP_HAS_NO_RVALUE_REFERENCES
 #endif
diff --git a/include/cmath b/include/cmath
index 8b7f2cf..4d92841 100644
--- a/include/cmath
+++ b/include/cmath
@@ -297,12 +297,6 @@
 
 */
 
-// FIXME: work around for Clang with -std=C++0x on OSX/iOS
-#if defined(__clang__) && defined(__APPLE__)
-# pragma push_macro("__STRICT_ANSI__")
-# undef __STRICT_ANSI__
-#endif  // defined(__clang__) && defined(__APPLE__)
-
 #include <__config>
 #include <math.h>
 #include <type_traits>
@@ -1587,9 +1581,4 @@
 
 _LIBCPP_END_NAMESPACE_STD
 
-// FIXME: work around for Clang with -std=C++0x on OSX/iOS
-#if defined(__clang__) && defined(__APPLE__)
-# pragma pop_macro("__STRICT_ANSI__")
-#endif
-
 #endif  // _LIBCPP_CMATH
diff --git a/include/cstddef b/include/cstddef
index def48bc..33886d4 100644
--- a/include/cstddef
+++ b/include/cstddef
@@ -78,42 +78,6 @@
     friend _LIBCPP_ALWAYS_INLINE bool operator<=(nullptr_t, nullptr_t) {return true;}
     friend _LIBCPP_ALWAYS_INLINE bool operator>(nullptr_t, nullptr_t) {return false;}
     friend _LIBCPP_ALWAYS_INLINE bool operator>=(nullptr_t, nullptr_t) {return true;}
-
-    template <typename _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator==(nullptr_t, _Tp* __p) {return 0 == __p;}
-
-    template <typename _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator==(_Tp* __p, nullptr_t) {return __p == 0;}
-
-    template <class _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator!=(nullptr_t, _Tp* __p) {return 0 != __p;}
-
-    template <class _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator!=(_Tp* __p, nullptr_t) {return __p != 0;}
-
-    template <class _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator<(nullptr_t, _Tp* __p) {return 0 < __p;}
-
-    template <class _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator<(_Tp* __p, nullptr_t) {return __p < 0;}
-
-    template <class _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator<=(nullptr_t, _Tp* __p) {return 0 <= __p;}
-
-    template <class _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator<=(_Tp* __p, nullptr_t) {return __p <= 0;}
-
-    template <class _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator>(nullptr_t, _Tp* __p) {return 0 > __p;}
-
-    template <class _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator>(_Tp* __p, nullptr_t) {return __p > 0;}
-
-    template <class _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator>=(nullptr_t, _Tp* __p) {return 0 >= __p;}
-
-    template <class _Tp>
-        friend _LIBCPP_ALWAYS_INLINE bool operator>=(_Tp* __p, nullptr_t) {return __p >= 0;}
 };
 
 inline _LIBCPP_ALWAYS_INLINE nullptr_t __get_nullptr_t() {return nullptr_t(0);}
diff --git a/include/iterator b/include/iterator
index f1a4f9c..7001c35 100644
--- a/include/iterator
+++ b/include/iterator
@@ -1616,7 +1616,7 @@
 
 #endif  // _LIBCPP_DEBUG
 
-#if !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_DECLTYPE)
+#if !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_TRAILING_RETURN)
 
 template <class _C>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1650,7 +1650,7 @@
     return __c.end();
 }
 
-#else  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_DECLTYPE)
+#else  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_TRAILING_RETURN)
 
 template <class _C>
 inline _LIBCPP_INLINE_VISIBILITY
@@ -1684,7 +1684,7 @@
     return __c.end();
 }
 
-#endif  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_DECLTYPE)
+#endif  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_TRAILING_RETURN)
 
 template <class _T, size_t _N>
 inline _LIBCPP_INLINE_VISIBILITY
diff --git a/include/memory b/include/memory
index 86da721..c016154 100644
--- a/include/memory
+++ b/include/memory
@@ -1471,7 +1471,7 @@
 {
 };
 
-#if !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_ADVANCED_SFINAE)
+#if !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)
 
 // uses-allocator construction
 
@@ -1489,7 +1489,7 @@
     : integral_constant<int, __uses_alloc_ctor_imp<_Tp, _Alloc, _Args...>::value>
     {};
 
-#endif  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES) && !defined(_LIBCPP_HAS_NO_ADVANCED_SFINAE)
+#endif  // !defined(_LIBCPP_HAS_NO_RVALUE_REFERENCES)
 
 // allocator
 
diff --git a/include/thread b/include/thread
index 7b6cf93..a4d3c4c 100644
--- a/include/thread
+++ b/include/thread
@@ -253,13 +253,8 @@
 {
     pthread_t __t_;
 
-#ifndef _LIBCPP_HAS_NO_DELETED_FUNCTIONS
-    thread(const thread&) = delete;
-    thread& operator=(const thread&) = delete;
-#else  // _LIBCPP_HAS_NO_DELETED_FUNCTIONS
     thread(const thread&);
     thread& operator=(const thread&);
-#endif  // _LIBCPP_HAS_NO_DELETED_FUNCTIONS
 public:
     typedef __thread_id id;
     typedef pthread_t native_handle_type;
diff --git a/include/type_traits b/include/type_traits
index 82d1f91..d3318cd 100644
--- a/include/type_traits
+++ b/include/type_traits
@@ -1254,9 +1254,8 @@
     static _Tp __t();
     static _Up __u();
 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
-    static bool __f();
 public:
-    typedef decltype(__f() ? __t() : __u()) type;
+    typedef decltype(true ? __t() : __u()) type;
 };
 
 #else  // _LIBCPP_HAS_NO_VARIADICS
@@ -1335,11 +1334,10 @@
 typename remove_reference<_Tp>::type&&
 move(_Tp&& __t)
 {
-    return static_cast<typename remove_reference<_Tp>::type&&>(__t);
+    typedef typename remove_reference<_Tp>::type _Up;
+    return static_cast<_Up&&>(__t);
 }
 
-#if 1
-
 template <class _Tp>
 inline _LIBCPP_INLINE_VISIBILITY
 _Tp&&
@@ -1358,54 +1356,6 @@
  	return static_cast<_Tp&&>(__t);
 }
 
-#else
-
-template <class _Tp,
-          class = typename enable_if<
-                     !is_lvalue_reference<_Tp>::value
-                  >::type
-         >
-inline _LIBCPP_INLINE_VISIBILITY
-_Tp&&
-forward(typename common_type<_Tp>::type& __t)
-{
-    return static_cast<_Tp&&>(__t);
-}
-
-template <class _Tp,
-          class = typename enable_if<
-                     !is_lvalue_reference<_Tp>::value
-                  >::type
-         >
-inline _LIBCPP_INLINE_VISIBILITY
-_Tp&&
-forward(typename common_type<_Tp>::type&& __t)
-{
-    return static_cast<_Tp&&>(__t);
-}
-
-template <class _Tp,
-          class = typename enable_if<
-                     is_lvalue_reference<_Tp>::value
-                  >::type
-         >
-inline _LIBCPP_INLINE_VISIBILITY
-_Tp
-forward(typename common_type<_Tp>::type __t)
-{
-    return __t;
-}
-
-template <class _Tp,
-          class = typename enable_if<
-                     is_lvalue_reference<_Tp>::value
-                  >::type
-         >
-_Tp
-forward(typename remove_reference<_Tp>::type&& __t) = delete;
-
-#endif
-
 #else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
 
 template <class _Tp>
diff --git a/include/utility b/include/utility
index 1c1e4a3..3a6847a 100644
--- a/include/utility
+++ b/include/utility
@@ -218,8 +218,6 @@
               second(_STD::forward<_U2>(__u2))
             {}
 
-#ifndef _LIBCPP_HAS_NO_VARIADICS
-
     template<class _Tuple,
              class = typename enable_if<__tuple_convertible<_Tuple, pair>::value>::type>
         _LIBCPP_INLINE_VISIBILITY
@@ -230,6 +228,8 @@
                                    typename __make_tuple_types<_Tuple>::type>::type>(get<1>(__p)))
             {}
 
+#ifndef _LIBCPP_HAS_NO_VARIADICS
+
     template <class... _Args1, class... _Args2, size_t... _I1, size_t... _I2>
         _LIBCPP_INLINE_VISIBILITY
         pair(piecewise_construct_t __pc, tuple<_Args1...> __first_args,
@@ -239,6 +239,8 @@
                    typename __make_tuple_indices<sizeof...(_Args2) >::type())
             {}
 
+#endif  // _LIBCPP_HAS_NO_VARIADICS
+
     template <class _Tuple,
               class = typename enable_if<__tuple_assignable<_Tuple, pair>::value>::type>
         _LIBCPP_INLINE_VISIBILITY
@@ -253,8 +255,6 @@
             return *this;
         }
 
-#endif  // _LIBCPP_HAS_NO_VARIADICS
-
 #else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
     template<class _U1, class _U2>
         _LIBCPP_INLINE_VISIBILITY pair(const pair<_U1, _U2>& __p)