Add documentation for rebind C++03 compatibility

doc/pointer_traits.qbk

@@ -113,6 +113,9 @@ also not defined (`pointer_traits` is SFINAE-friendly).
   where `Args` is zero or more type arguments; otherwise, the member is not
   defined.]]]
 
+[note When C++11 template aliases are not supported, the `type` for `rebind` is
+`T::rebind<U>::other` if such a type exists.]
+
 [endsect]
 
 [section Member functions]

include/boost/core/pointer_traits.hpp

@@ -100,11 +100,19 @@ template<class T, class U, class = void>
 struct ptr_rebind
     : ptr_transform<T, U> { };
 
+#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
 template<class T, class U>
 struct ptr_rebind<T, U,
     typename ptr_valid<typename T::template rebind<U> >::type> {
     typedef typename T::template rebind<U> type;
 };
+#else
+template<class T, class U>
+struct ptr_rebind<T, U,
+    typename ptr_valid<typename T::template rebind<U>::other>::type> {
+    typedef typename T::template rebind<U>::other type;
+};
+#endif
 
 #if !defined(BOOST_NO_CXX11_DECLTYPE_N3276)
 template<class T, class E>

test/pointer_traits_rebind_sfinae_test.cpp

@@ -56,7 +56,7 @@ struct P3 {
     typedef int element_type;
 
     template<class>
-    struct rebind { };
+    using rebind = P3;
 };
 
 template<class T>

test/pointer_traits_sfinae_test.cpp

@@ -64,8 +64,15 @@ struct P2 {
 struct P3 {
     typedef int element_type;
 
+#if !defined(BOOST_NO_CXX11_TEMPLATE_ALIASES)
     template<class>
-    struct rebind { };
+    using rebind = P3;
+#else
+    template<class>
+    struct rebind {
+        typedef P3 other;
+    };
+#endif
 };
 
 template<class T>