mkdir_ok. straightforward spec based on DirTree's mkdir.  if we want to do something with the created directory, we probably need to change the spec of mkdir, in a similar style to the change for create_ok and mkfile.
mkdir_ok. straightforward spec based on DirTree's mkdir.  if we want to do something
with the created directory, we probably need to change the spec of mkdir, in a similar
style to the change for create_ok and mkfile.

mit-pdos/fscq-impl,mit-pdos/fscq-impl,mit-pdos/fscq-impl,mit-pdos/fscq-impl,mit-pdos/fscq-impl