diff --git a/include/__config b/include/__config
index a3518d9..4279736 100644
--- a/include/__config
+++ b/include/__config
@@ -73,6 +73,76 @@
 
 #define _LIBCPP_ALWAYS_INLINE  __attribute__((__always_inline__))
 
+#if defined(__clang__)
+
+#if !(__has_feature(cxx_exceptions))
+#define _LIBCPP_NO_EXCEPTIONS
+#endif
+
+#define _LIBCPP_HAS_NO_ADVANCED_SFINAE
+#define _LIBCPP_HAS_NO_STRONG_USING
+#define _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+
+#ifndef __GXX_EXPERIMENTAL_CXX0X__
+
+#define _LIBCPP_HAS_NO_DECLTYPE
+#define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+#define _LIBCPP_HAS_NO_DELETED_FUNCTIONS
+#define _LIBCPP_HAS_NO_NULLPTR
+#define _LIBCPP_HAS_NO_STATIC_ASSERT
+#define _LIBCPP_HAS_NO_UNICODE_CHARS
+#define _LIBCPP_HAS_NO_VARIADICS
+
+#else
+
+#if __has_feature(cxx_rvalue_references)
+#define _LIBCPP_MOVE
+#endif
+
+#if !(__has_feature(cxx_decltype))
+#define _LIBCPP_HAS_NO_DECLTYPE
+#endif
+
+#if !(__has_feature(cxx_deleted_functions))
+#define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+#define _LIBCPP_HAS_NO_DELETED_FUNCTIONS
+#endif
+
+#if !(__has_feature(cxx_nullptr))
+#define _LIBCPP_HAS_NO_NULLPTR
+#endif
+
+#if !(__has_feature(cxx_static_assert))
+#define _LIBCPP_HAS_NO_STATIC_ASSERT
+#endif
+
+#if !(__has_feature(cxx_variadic_templates))
+#define _LIBCPP_HAS_NO_VARIADICS
+#endif
+
+#endif
+
+#elif defined(__GNUC__)
+
+#if !__EXCEPTIONS
+#define _LIBCPP_NO_EXCEPTIONS
+#endif
+
+#define _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+
+#ifndef __GXX_EXPERIMENTAL_CXX0X__
+
+#define _LIBCPP_HAS_NO_ADVANCED_SFINAE
+#define _LIBCPP_HAS_NO_DECLTYPE
+#define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+#define _LIBCPP_HAS_NO_DELETED_FUNCTIONS
+#define _LIBCPP_HAS_NO_NULLPTR
+#define _LIBCPP_HAS_NO_STATIC_ASSERT
+#define _LIBCPP_HAS_NO_UNICODE_CHARS
+#define _LIBCPP_HAS_NO_VARIADICS
+
+#else
+
 #if __GNUC__ >= 4 && __GNUC_MINOR__ >= 3
 #define _LIBCPP_MOVE
 #endif
@@ -81,23 +151,22 @@
 #define _LIBCPP_HAS_NO_STATIC_ASSERT
 #endif
 
-#define _LIBCPP_HAS_NO_NULLPTR
-
-#if !(__GNUC__ >= 4 && __GNUC_MINOR__ >= 3)
-#define _LIBCPP_HAS_NO_VARIADICS
-#define _LIBCPP_HAS_NO_DECLTYPE
-#endif
-
 #if !(__GNUC__ >= 4 && __GNUC_MINOR__ >= 4)
-#define _LIBCPP_HAS_NO_UNICODE_CHARS
 #define _LIBCPP_HAS_NO_ADVANCED_SFINAE
+#define _LIBCPP_HAS_NO_DECLTYPE
+#define _LIBCPP_HAS_NO_DEFAULTED_FUNCTIONS
+#define _LIBCPP_HAS_NO_DELETED_FUNCTIONS
+#define _LIBCPP_HAS_NO_UNICODE_CHARS
+#define _LIBCPP_HAS_NO_VARIADICS
 #endif
 
-#if defined(__clang__)
-#define _LIBCPP_HAS_NO_STRONG_USING
+#if !(__GNUC__ >= 4 && __GNUC_MINOR__ >= 6)
+#define _LIBCPP_HAS_NO_NULLPTR
 #endif
 
-#define _LIBCPP_HAS_NO_TEMPLATE_ALIASES
+#endif
+
+#endif
 
 #ifdef _LIBCPP_HAS_NO_STRONG_USING
 #define _LIBCPP_BEGIN_NAMESPACE_STD namespace std {
@@ -106,6 +175,7 @@
 #else
 #define _LIBCPP_BEGIN_NAMESPACE_STD namespace std { namespace _LIBCPP_NAMESPACE {
 #define _LIBCPP_END_NAMESPACE_STD  } }
+#define _STD std::_LIBCPP_NAMESPACE
 
 namespace std {
 namespace _LIBCPP_NAMESPACE {
@@ -113,12 +183,11 @@
 using namespace _LIBCPP_NAMESPACE __attribute__((__strong__));
 }
 
-#define _STD std::_LIBCPP_NAMESPACE
 #endif
 
 #ifdef _LIBCPP_HAS_NO_UNICODE_CHARS
-    typedef unsigned short char16_t;
-    typedef unsigned int   char32_t;
+typedef unsigned short char16_t;
+typedef unsigned int   char32_t;
 #endif
 
 #ifdef _LIBCPP_HAS_NO_STATIC_ASSERT
@@ -133,13 +202,7 @@
 #endif
 
 #ifdef _LIBCPP_HAS_NO_DECLTYPE
-
 #define decltype(x) __typeof__(x)
-
-#endif
-
-#if !__EXCEPTIONS
-#define _LIBCPP_NO_EXCEPTIONS
 #endif
 
 #endif  // _LIBCPP_CONFIG
diff --git a/include/cmath b/include/cmath
index 1fe8479..f133de9 100644
--- a/include/cmath
+++ b/include/cmath
@@ -297,6 +297,12 @@
 
 */
 
+// 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
+
 #include <__config>
 #include <math.h>
 #include <type_traits>
@@ -1641,4 +1647,9 @@
 
 _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 f6b34ad..8cba5f8 100644
--- a/include/cstddef
+++ b/include/cstddef
@@ -78,6 +78,42 @@
     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 f2173e9..877474b 100644
--- a/include/iterator
+++ b/include/iterator
@@ -1615,7 +1615,7 @@
 
 #endif  // _LIBCPP_DEBUG
 
-#ifdef _LIBCPP_MOVE
+#if defined(_LIBCPP_MOVE) && !defined(_LIBCPP_HAS_NO_DECLTYPE)
 
 template <class _C>
 inline
diff --git a/include/memory b/include/memory
index 8af5ed7..3358a19 100644
--- a/include/memory
+++ b/include/memory
@@ -1129,7 +1129,7 @@
 {
 };
 
-#ifdef _LIBCPP_MOVE
+#if defined(_LIBCPP_MOVE) && !defined(_LIBCPP_HAS_NO_ADVANCED_SFINAE)
 
 // uses-allocator construction
 
diff --git a/include/string b/include/string
index 3428fb8..2ca5986 100644
--- a/include/string
+++ b/include/string
@@ -1259,8 +1259,6 @@
     _LIBCPP_INLINE_VISIBILITY const allocator_type& __alloc() const {return __r_.second();}
 
     _LIBCPP_INLINE_VISIBILITY bool __is_long() const {return bool(__r_.first().__s.__size_ & __short_mask);}
-    _LIBCPP_INLINE_VISIBILITY void __set_long()  {__r_.first().__s.__size_ &= __short_mask;}
-    _LIBCPP_INLINE_VISIBILITY void __set_short() {__r_.first().__s.__size_ |= ~__short_mask;}
 
     _LIBCPP_INLINE_VISIBILITY void __set_short_size(size_type __s)
 #if _LIBCPP_BIG_ENDIAN
diff --git a/include/thread b/include/thread
index 5fcd2c9..6bf3189 100644
--- a/include/thread
+++ b/include/thread
@@ -178,9 +178,12 @@
 {
     pthread_t __t_;
 
-#ifndef _LIBCPP_MOVE
-    thread(const thread&); // = delete;
-    thread& operator=(const thread&); // = delete;
+#ifndef _LIBCPP_HAS_NO_DELETED_FUNCTIONS
+    thread(const thread&) = delete;
+    thread& operator=(const thread&) = delete;
+#else
+    thread(const thread&);
+    thread& operator=(const thread&);
 #endif
 public:
     typedef __thread_id id;
@@ -201,9 +204,7 @@
     ~thread();
 
 #ifdef _LIBCPP_MOVE
-    thread(const thread&) = delete;
     thread(thread&& __t) : __t_(__t.__t_) {__t.__t_ = 0;}
-    thread& operator=(const thread&) = delete;
     thread& operator=(thread&& __t);
 #endif
 
diff --git a/include/type_traits b/include/type_traits
index 73b7a99..fc14471 100644
--- a/include/type_traits
+++ b/include/type_traits
@@ -1093,10 +1093,10 @@
 #else
     static _Tp __t();
     static _Up __u();
-    static bool __f();
 #endif
+    static bool __f();
 public:
-    typedef __typeof__(__f() ? __t() : __u()) type;
+    typedef decltype(__f() ? __t() : __u()) type;
 };
 
 #else
@@ -1135,7 +1135,10 @@
 template <class _Tp>
 inline _LIBCPP_INLINE_VISIBILITY
 typename remove_reference<_Tp>::type&&
-move(_Tp&& __t) {return __t;}
+move(_Tp&& __t)
+{
+    return static_cast<typename remove_reference<_Tp>::type&&>(__t);
+}
 
 template <class _Tp, class _Up,
     class = typename _STD::enable_if<
@@ -1148,8 +1151,7 @@
 _Tp&&
 forward(_Up&& __t)
 {
-    return __t;  // to quiet spurious warning
-//    return static_cast<_Tp&&>(__t);
+    return static_cast<_Tp&&>(__t);
 }
 
 #else  // _LIBCPP_MOVE
diff --git a/include/utility b/include/utility
index 578d313..19e2893 100644
--- a/include/utility
+++ b/include/utility
@@ -223,6 +223,8 @@
               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
@@ -233,7 +235,6 @@
                                    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>
         pair(piecewise_construct_t __pc, tuple<_Args1...> __first_args,
                                     tuple<_Args2...> __second_args)
@@ -241,7 +242,6 @@
                    typename __make_tuple_indices<sizeof...(_Args1)>::type(),
                    typename __make_tuple_indices<sizeof...(_Args2) >::type())
             {}
-#endif
 
     template <class _Tuple,
               class = typename enable_if<__tuple_assignable<_Tuple, pair>::value>::type>
@@ -256,6 +256,8 @@
             return *this;
         }
 
+#endif
+
 #else
     template<class _U1, class _U2>
         _LIBCPP_INLINE_VISIBILITY pair(const pair<_U1, _U2>& __p)
diff --git a/test/language.support/support.types/nullptr_t.pass.cpp b/test/language.support/support.types/nullptr_t.pass.cpp
index b169f1a..204d740 100644
--- a/test/language.support/support.types/nullptr_t.pass.cpp
+++ b/test/language.support/support.types/nullptr_t.pass.cpp
@@ -24,9 +24,10 @@
                   "sizeof(std::nullptr_t) == sizeof(void*)");
     A* p = 0;
     assert(p == nullptr);
+    assert(nullptr == p);
+#if !((__GNUC__ < 4) || (__GNUC__ == 4 && __GNUC_MINOR__ <= 5))
+    // GCC 4.2 through 4.5 can't handle this
     void (A::*pmf)() = 0;
-#ifdef __clang__
-    // GCC 4.2 can't handle this
     assert(pmf == nullptr);
 #endif
     int A::*pmd = 0;
@@ -41,4 +42,20 @@
     assert(!(nullptr != nullptr));
     assert(!(nullptr < nullptr));
     assert(!(nullptr > nullptr));
+    assert(!(&a1 == nullptr));
+    assert(!(nullptr == &a1));
+    assert(&a1 != nullptr);
+    assert(nullptr != &a1);
+    assert(nullptr < &a1);
+    assert(nullptr <= &a1);
+    assert(!(nullptr < p));
+    assert(nullptr <= p);
+    assert(!(&a1 < nullptr));
+    assert(!(&a1 <= nullptr));
+    assert(!(p < nullptr));
+    assert(p <= nullptr);
+    assert(!(nullptr > &a1));
+    assert(!(nullptr >= &a1));
+    assert(!(nullptr > p));
+    assert(nullptr >= p);
 }