How do I make an automake rule in an .mk file that deletes a directory upon cleaning?

I would like to delete a another dir开发者_运维问答ectory when I run make clean, but I can't figure out how to code it up in the rules.

I have tried

clean-local:
  -rm -f del.dir

but that didn't work.

I also tried

CLEANFILES = del.dir

but that also didn't work.

Any suggestions would be appreciated,

clean-local should work, but the command to erase a directory is rm -rf dir, not rm -f dir.