OCaml 4.06.0 pulls the Num module out of stdlib into its own separate project. Nominally it's possible to maintain backwards compatibility by simply installing the now-separate Num (opam!) and presumably tweaking package info to pull in the now-external dependency. But as far as I can tell, it's totally impossible to do this on a machine that's ever had any previous version of ocaml installed. It may not be possible to do it on a fresh install, either; I wouldn't know.
tl;dr: ocamlfind couldn't find the new Num. There seems to be a solution involving pinning ocamlfind back to some previous version (see: https://github.com/BinaryAnalysisPlatform/bap/issues/742), but that didn't work for me.
So. The recommendation is to use ZArith instead of Num anyway. Zarith is apparently a better, faster implementation of arbitrary-precision integers/rationals (https://github.com/ocaml/Zarith). Since building CIL with 4.06 involve adding an external dependency (to either Num or Zarith) and Num was giving me nightmares, I thought I'd try my hand at just replacing Num with Zarith and updating Cilint accordingly.
(TBH the rationale for continuing to wrap what-used-to-be-Bigint in Cilint isn't obvious to me, but that was a bigger refactor than I was willing to make without confirmation/blessing from the project owners/maintainers.)
Confirmed to build on 4.06+trunk, on Darwin and some arbitrary Ubuntu flavor (don't remember which one, I can check if you care), passes no fewer tests after than before.
Tricky bits:
4.06 enforces some deprecation that previously only resulted in a warning, so this PR includes commits that address deprecation warnings that I included in (https://github.com/cil-project/cil/pull/40)
I don't know how far back in the OCaml release history this will work. I was thinking that, in your shoes, I'd have a separate dev branch for experimental 4.06 support. But, since you don't have one, I just issue my PR and leave it to you.
OCaml 4.06.0 pulls the Num module out of stdlib into its own separate project. Nominally it's possible to maintain backwards compatibility by simply installing the now-separate Num (opam!) and presumably tweaking package info to pull in the now-external dependency. But as far as I can tell, it's totally impossible to do this on a machine that's ever had any previous version of ocaml installed. It may not be possible to do it on a fresh install, either; I wouldn't know.
tl;dr: ocamlfind couldn't find the new Num. There seems to be a solution involving pinning ocamlfind back to some previous version (see: https://github.com/BinaryAnalysisPlatform/bap/issues/742), but that didn't work for me.
So. The recommendation is to use ZArith instead of Num anyway. Zarith is apparently a better, faster implementation of arbitrary-precision integers/rationals (https://github.com/ocaml/Zarith). Since building CIL with 4.06 involve adding an external dependency (to either Num or Zarith) and Num was giving me nightmares, I thought I'd try my hand at just replacing Num with Zarith and updating Cilint accordingly.
(TBH the rationale for continuing to wrap what-used-to-be-Bigint in Cilint isn't obvious to me, but that was a bigger refactor than I was willing to make without confirmation/blessing from the project owners/maintainers.)
Confirmed to build on 4.06+trunk, on Darwin and some arbitrary Ubuntu flavor (don't remember which one, I can check if you care), passes no fewer tests after than before.
Tricky bits: