If you generate the Lisp files, do you need to check in the .spec files?
there's a strong argument for keeping the spec files: if the cffi/c2ffi generator itself gets a bug fix/upgrade, then the lisp files would need to be regenerated for those fixes/upgrades to take effect, and that's only possible if the spec files are available.
which, BTW, currently happens automagically due to that unlucky component -> system dependency on the "cffi/c2ffi-generator" system.
thanks for the review!