The output I got from this and dist-no-built-sources.log is rather interesting. As it looks, the test is indeed broken from the beginning.
Thank you very much, Jens. We'll deal with this asap. Your original analysis that we simply don't recognize the right option name is looking correct :) :(. (Bogdan, want to give it a look? I am consumed with other projects for the time being.) --thanks, karl.