* dtable.cc (dtable::delete_archetype): Add debugging.

* dtable.cc (dtable::delete_archetype): Add debugging.
(dtable::release): Move archetype deletion here.
(dtable::vfork_child_dup): Increment ctty usecount to catch later
close_all_files case in parent/child.
(dtable::vfork_child_fixup): Avoid using cygheap->foo where this should really
be using local references.  Call close on archetyped handles since the handles
haven't had the noninherit flag set.
* fhandler_tty.cc (fhandler_tty_slave::close): Remove archetype deletion code.
Add defensive error message when DEBUGGING.
(fhandler_tty_common::set_close_on_exec): Use more robust method for checking
whether to set handles into noninherit if there is an archetype associated with
the fhandler.