{ \
  template<typename _Ay> \
  class list<__VA_ARGS__, _Ay>  \
    : public list<__VA_ARGS__, EIGEN_ALIGNED_ALLOCATOR<__VA_ARGS__> > \
  { \
    typedef list<__VA_ARGS__, EIGEN_ALIGNED_ALLOCATOR<__VA_ARGS__> > list_base; \
  public: \
    typedef __VA_ARGS__ value_type; \
    typedef typename list_base::allocator_type allocator_type; \
    typedef typename list_base::size_type size_type;  \
    typedef typename list_base::iterator iterator;  \
    explicit list(const allocator_type& a = allocator_type()) : list_base(a) {}  \
    template<typename InputIterator> \
    list(InputIterator first, InputIterator last, const allocator_type& a = allocator_type()) : list_base(first, last, a) {} \
    list(const list& c) : list_base(c) {}  \
    explicit list(size_type num, const value_type& val = value_type()) : list_base(num, val) {} \
    list(iterator start, iterator end) : list_base(start, end) {}  \
    list& operator=(const list& x) {  \
      list_base::operator=(x);  \
      return *this;  \
    } \
  }; \
}
#define EIGEN_EXPLICIT_STL_LIST_INSTANTIATION(...)
This section contains a convenience MACRO which allows an easy specialization of std::list such that for data types with alignment issues the correct allocator is used automatically.