anchor.diff:  
   let alt-ergo-lib = ocamlPackages.buildDunePackage rec {
     pname = "alt-ergo-lib";
  -  inherit version src preConfigure nativeBuildInputs;
  +  inherit version src nativeBuildInputs;
     configureFlags = pname;
     propagatedBuildInputs = with ocamlPackages; [ num ocplib-simplex stdlib-shims zarith ];
   }; in
   
   let alt-ergo-parsers = ocamlPackages.buildDunePackage rec {
     pname = "alt-ergo-parsers";
  -  inherit version src preConfigure nativeBuildInputs;
  +  inherit version src nativeBuildInputs;
     configureFlags = pname;
     buildInputs = with ocamlPackages; [ menhir ];
     propagatedBuildInputs = [ alt-ergo-lib ] ++ (with ocamlPackages; [ camlzip psmt2-frontend ]);
  
positive.code: 
  let
    pname = "alt-ergo";
    version = "2.3.2";
  
    src = fetchurl {
      url = "https://alt-ergo.ocamlpro.com/http/alt-ergo-${version}/alt-ergo-${version}.tar.gz";
      sha256 = "130hisjzkaslygipdaaqib92spzx9rapsd45dbh5ssczjn5qnhb9";
    };
  
    preConfigure = "patchShebangs ./configure";
  
    nativeBuildInputs = [ which ];
  
  
negative.code: 
  ocamlPackages.buildDunePackage {
  
    inherit pname version src nativeBuildInputs;
  
    configureFlags = pname;
  
  