2012-04-13  Paolo Carlini  <paolo.carlini@oracle.com>

	* include/debug/safe_iterator.h (_BeforeBeginHelper<>::
	_S_Is_Beginnest): Add.
	* include/debug/forward_list (_BeforeBeginHelper<>::
	_S_Is_Beginnest): Likewise.
	(_Safe_iterator<>::_M_is_beginnest): Add.
	* include/debug/safe_iterator.tcc (_Safe_iterator<>::_M_valid_range):
	Use the latter.
	* testsuite/23_containers/forward_list/debug/splice_after.cc:
	Add test.

From-SVN: r186411