You should speak with a lawyer if you have any doubts.

Thanks, I know the litany :-). And if I have occasion to need a concrete answer to a question which is really doubtful I will. But the always-correct answer "you should talk to a lawyer" does not help someone who cannot or does not want to talk to a lawyer and just wants to know "Can I take this module and use it at work." or "Can I copy this subroutine into my own program". That's an entry-barrier into using OS software which we can do without. No programmers I know like dealing with legal stuff and if they come up with such a question and don't easily find an answer they may decide to not bother and wander off to use C# instead. I believe that most of these questions can be answered in general with a fair amount of accuracy by a knowledgeable person, and having these answers available would be a good thing.

Anyway, I'm happy with chromatics answer, so no need to butt heads over this.