```
$ cd lib/libc
$ git revert -n cbdec8db18b5
$ make cleandir
$ make -s WITHOUT_TESTS=
$ git checkout -f
$ make -s WITHOUT_TESTS= # fails
$ cd ../../
$ sh tools/build/depend-cleanup.sh /usr/obj/usr/home/markj/src/freebsd/amd64.amd64
Removing stale dependencies for pdfork.S
$ sh tools/build/depend-cleanup.sh /usr/obj/usr/home/markj/src/freebsd/amd64.amd64
$ cd lib/libc
$ make -s WITHOUT_TESTS= # succeeds
```