Greets, Thanks for working on this, Niels, and thanks for following up on it, Mark. It's great to have such knowledgeable folk working on this problem.
One suggestion, if it's possible: it would be great if mini-gmp could make it to be part of gnulib at some point. That's probably the easiest way of providing this functionality to all GNU programs, in a way that allows changes to mini-gmp to propagate to their users (via the gnulib update mechanism). Cheers, Andy -- http://wingolog.org/