anchor.diff: -{ lib, fetchurl, buildDunePackage, ounit, cstruct, dune-configurator, eqaf, pkg-config
  +{ lib, fetchurl, buildDunePackage, ounit, cstruct, dune-configurator, eqaf, bigarray-compat, pkg-config
   , withFreestanding ? false
   , ocaml-freestanding
   }:
  
positive.code: 
    nativeBuildInputs = [ dune-configurator pkg-config ];
    propagatedBuildInputs = [
      cstruct eqaf
    ] ++ lib.optionals withFreestanding [
      ocaml-freestanding
    ];
  
negative.code:   minimumOCamlVersion = "4.08";
  
    pname = "mirage-crypto";
    version = "0.10.0";
  
    src = fetchurl {
      url = "https://github.com/mirage/mirage-crypto/releases/download/v${version}/mirage-crypto-v${version}.tbz";
      sha256 = "20915c53ddb658c53f588c414f13676bc8ad3cd734d9ed909225ea080dd8144d";
    };
  
    useDune2 = true;
  