Since this was a bug, I felt I should move on it before this week's release. In r30279 I applied a modified version of the patch submitted earlier: I added $conf->cc_clean() at one location.
I then trimmed the list of configuration steps to end at auto::attributes and reconfigured. An 'ls' on my top-level directory indicated that no 'test*' files had been created. So that is evidence that the patch did its job. But I think there may still be 'test*' files left over either from Configure.pl or the preconfiguration tests, and I will keep trying to track them down. Thank you very much. kid51
