forward_list.h (forward_list<>::erase_after): Return an iterator.

forward_list.h (forward_list<>::erase_after): Return an iterator.

2010-10-17  Paolo Carlini  <paolo.carlini@oracle.com>

	* include/bits/forward_list.h (forward_list<>::erase_after): Return
	an iterator.
	(_M_erase_after): Return _Fwd_list_node_base*.
	* include/bits/forward_list.tcc: Likewise.
	* include/debug/forward_list: Likewise.
	* testsuite/23_containers/forward_list/modifiers/3.cc: Update
	and extend.
	* testsuite/util/exception/safety.h (erase_base<forward_list<>>):
	Adjust.
	* testsuite/23_containers/forward_list/requirements/dr438/
	assign_neg.cc: Adjust dg-error line number.
	* testsuite/23_containers/forward_list/requirements/dr438/
	insert_neg.cc: Likewise.
	* testsuite/23_containers/forward_list/requirements/dr438/
	constructor_1_neg.cc: Likewise.
	* testsuite/23_containers/forward_list/requirements/dr438/
	constructor_2_neg.cc: Likewise.

From-SVN: r165590