It seems Apple's terms are incompatible with copyleft, and that isn't
likely to change. Is there any copylefted code in TBB? I would
expect so, but I haven't enumerated it. People who choose copyleft
for their code do so for a reason, and Apple's terms are fundamentally
inconsistent with those reasons - this isn't a matter of nits to be
smoothed over.
Is the agreement that a company would have to sign public? There
seems to be some notion that it is not. I believe that charitable
organizations and free software organizations should not enter into
secret agreements, and that doing so would be a breach of their duty
to act in the public interest.