shared_ptr tests have warnings on linux

[nobody]

1. warning: `class n_spt_abstract::X' 
   has virtual functions but non-virtual destructor
   Resolution: add virtual keyword to destructor
2. warning: `class 
   n_spt_shared_from_this::X' has virtual functions but
non-virtual destructor
   Resolution: add virtual keyword to destructor
3. warning: `class 
   n_spt_shared_from_this::Y' has virtual functions but
non-virtual destructor
   Resolution: add virtual keyword to destructor
4. warning: `class 
   n_spt_shared_from_this::impl' has virtual functions
but non-virtual 
   destructor
   Resolution: same as above

Might I suggest that the Boost community crank up their
warning levels and clean up their code too?

[Peter Dimov]

Logged In: YES 
user_id=305912

The lack of virtual destructor is part of what is being tested.

shared_ptr supports classes with non-virtual destructors.