bind2nd, ptr_fun with a function with const refs args.

[Steven King]

I was trying to use bind2nd and ptr_fun with a function that has two const & 
args.  ie

template < typename T1, typename T2, typename T3 >
std::set < T3 >
bar (std::set < T1 > const &s, T2 const &t, T3 (*f)(T1 const &, T2 const &))
{
   std::set < T3 > r;
   std::transform (
      s.begin (), 
      s.end (), 
      std::inserter (r, r.begin ()), 
      bind2nd(ptr_fun (f), t));
   return r;
}

this fails an 'error: forming reference to reference type'.
  As I dont have a copy of the standard handy, I wasnt sure if this was 
supposed to work; if so, would it be reasonable to add to stl_function.h a 
specialization of pointer_to_binary_function like so:

template <class _Arg1, class _Arg2, class _Result>
class pointer_to_binary_function :
  public binary_function<const _Arg1&, const _Arg2&,_Result> {
protected:
    _Result (*_M_ptr)(const _Arg1&, const _Arg2&);
public:
    pointer_to_binary_function() {}
    explicit pointer_to_binary_function(_Result (*__x)(const _Arg1&, const 
_Arg2&))
      : _M_ptr(__x) {}
    _Result operator()(const _Arg1& __x, const _Arg2& __y) const {
      return _M_ptr(__x, __y);
    }
};