For files with "special" bits set, we would stat the relative
file name in the wrong directory, giving an erroneous ENOENT diagnostic.
This issue was introduced with commit v5.92-653-gc1994c1
which changed fts to not change directory on traversal.
* src/chmod.c (mode_changed): Use fts->fts_cwd_fd with fstatat rather
than stat. All callers changed.
* tests/chmod/c-option.sh: Add a test case.
* NEWS: Mention the fix.
Fixes http://bugs.gnu.org/17035