2011-01-05  François Dumont  <francois.cppdevs@free.fr>

        * include/debug/safe_base.h (_Safe_iterator_base::_M_unlink): New.
        * include/src/debug.cc: Use latter
        * include/debug/forward_list (forward_list<>::_M_swap):  Fix to
        correctly handle before_begin iterators.
        * testsuite/23_containers/forward_list/debug/swap.cc: Remove now 
        useless _GLIBCXX_DEBUG checks.

From-SVN: r168528