This appears to be a broken tar issue surounding hardlinks and Christos has backed it out. So perhaps update and rebuild and try again.
I can see why you refer to 9.33.37 as a version of NetBSD, but really it is not a name for a specific version. That last number is increased when there is an internal ABI change, but many other things happen within the operating system that do not change that version number. So it is probably best to give the time at which you updated.
