[boost] Potential scoped_ptr improvement

The incantation scoped_ptr<Base> x( new Derived ); will succeed and produce undefined behavior upon x's destruction unless Derived has a trivial or virtual d'tor. It would be pretty easy to prevent something like that from compiling when has_virtual_destructor<Base>::value is false. Thoughts? -- Dave Abrahams BoostPro Computing http://www.boostpro.com