use of c++11 template aliases is not showing up in doxygen output. For:

+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+namespace std
+{
+  /**
+   *  @brief  An alias to the base class for std::allocator.
+   *  @ingroup allocators
+   *
+   *  Used to set the std::allocator base class to
+   *  __gnu_cxx::__mt_alloc.
+   *
+   *  @tparam  _Tp  Type of allocated object.
+    */
+  template<typename _Tp>
+    using __allocator_base = __gnu_cxx::__mt_alloc<_Tp>;
+}
+#else
+// Define __mt_alloc as the base class to std::allocator.
+# define __allocator_base  __gnu_cxx::__mt_alloc
+#endif

 /**
   * @brief  The @a standard allocator, as per [20.4].
   *
   *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html
   *  for further details.
   */

namespace std
{
  template<typename _Tp>
    class allocator: public __allocator_base<_Tp>
    {
 ...

as the input source, expecting __allocator_base showing up as base class in std::allocator class documentation. But the using sytax for C++11 template aliases is not recognized.