* include/bits/forward_list.h (forward_list::assign): Dispatch to new
functions based on assignability of elements.
(forward_list::_M_assign): Add overloaded functions for assigning
via assignment or via clearing and insertion.
(forward_list::_M_assign_val): Likewise.
(forward_list::_M_move_assign(forward_list&&, false_type)): Do not
erase elements that are not moved.
* include/bits/forward_list.tcc (forward_list::operator=): Call
assign() to copy elements.
* testsuite/23_containers/forward_list/cons/10.cc: New.
* testsuite/23_containers/forward_list/cons/11.cc: New.
* testsuite/23_containers/forward_list/cons/12.cc: New.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@193057
138bc75d-0d04-0410-961f-
82ee72b054a4