Migrate to Zarith
Previously we had to keep the num library for the why3 library because we compiled the coq-plugin. Could we now migrate to zarith?
From the num website:
This is a legacy library. It used to be part of the core OCaml distribution (in otherlibs/num) but is now distributed separately. New applications that need arbitrary-precision arithmetic should use the Zarith library (https://github.com/ocaml/Zarith) instead of the Num library, and older applications that already use Num are encouraged to switch to Zarith. Zarith delivers much better performance than Num and has a nicer API.