(etc::set_last_modified): Remove obsolete function.
* path.cc (etc::change_possible): Revert type to bool.
(etc::test_file_change): Do not test for negative values of change_possible and
do not set it to -res.
(etc::dir_changed): When the handle is NULL, call memset instead of
test_file_changed. When the handle is invalid, return true.
(etc::file_changed): Remove unneeded check for !fn[n].
d8cde3a3ee