"CVS-Unknown" buildfarm failures?

meerkat and snake both have persistent "CVS-Unknown" failures in some
but not all branches. I can't see any evidence of an actual failure
in their logs though. What I do see is "?" entries about files that
shouldn't be there --- for instance, meerkat apparently needs a "make
distclean". If that's what's causing the failure report, could we
get the buildfarm to show a more useful status message? I'd always
assumed that "CVS-Unknown" suggested a transient problem such as
connection loss, and there wasn't any need for human intervention.

A more radical answer is to have the script go ahead and delete the
offending files itself, but I can see where that might not have good
fail-soft behavior ...

regards, tom lane