David> If libffi were like the C/C++ libraries and available David> consistently on all platforms there would be no need to consider David> including it in the source. However, it's becoming clear that on David> a significant range of platforms using it would require users to David> install libffi from source and/or to make non-trivial tweaks to David> their system. I think it's important to try and ensure that when David> users download the tar-ball from Sourceforge they should be able David> to compile and install Poly/ML with the least amount of trouble. David> It looks like that can best be achieved by including libffi David> within the source and building with that by default. Packagers David> and users with special requirements can override that if they David> need to. That approach would seem to overcome any objections.
Yes, it is quite common to have an autoconf option like --with-system-libffi to force linking to an existing shared library. I don't think there would be any objection to that.
Thanks for entering into this boring discussion ;-)