[boost] Minor update to all _ptr headers

From: Douglas Gregor (gregod_at_[hidden])
Date: 2002-08-26 12:13:18

I've applied a minor change to all _ptr headers (shared_ptr, scoped_ptr, 
weak_ptr, intrusive_ptr) that adds a detail function template 
'is_pointerlike_helper' that looks like this:

template<typename T>
type_traits::yes_type is_pointerlike_helper(const xxx_ptr<T>&, int);

I needed the ability to determine if a type 'T' is a pointer or smart pointer 
in Signals, and this helper is needed to create the is_pointerlike trait 
check. Changes committed to CVS; no regressions AFAICT.

        Doug