I've stumbled upon the following comment in ports/Mk/bsd.commands.mk:
> # XXX: this is a work-around for an obscure bug where
> # mount -t nullfs returns zero status on errors within
> # a make target
I cannot find a bug report for that. Is this comment still relevant after over 10 years?
trasz@, you've done some work recently on nullfs. Could it be related?