Unordered: Merge to release. Fixes #6522.

Fixes undefined macros, removes some unused code and fix some potential issues
for when `std::allocator_traits` is used.


[SVN r76943]

test/objects/minimal.hpp

@@ -333,7 +333,7 @@ namespace minimal
         typedef std::size_t size_type;
         typedef std::ptrdiff_t difference_type;
         typedef void_ptr void_pointer;
-        typedef void_const_ptr void_const_pointer;
+        typedef void_const_ptr const_void_pointer;
         typedef ptr<T> pointer;
         typedef const_ptr<T> const_pointer;
         typedef T& reference;