anchor.diff:    };
   in
   
  -buildOcaml rec {
  -  name = "zarith";
  +stdenv.mkDerivation rec {
  +  name = "ocaml${ocaml.version}-zarith-${version}";
     inherit (source) version;
     src = fetchurl { inherit (source) url sha256; };
  -
  -  minimumSupportedOcamlVersion = "3.12.1";
   
     nativeBuildInputs = [ pkgconfig ];
     buildInputs = [ ocaml findlib perl ];
     propagatedBuildInputs = [ gmp ];
   
  -  # needed so setup-hook.sh sets CAML_LD_LIBRARY_PATH for dllzarith.so
  -  hasSharedObjects = true;
  -
     patchPhase = "patchShebangs ./z_pp.pl";
     configurePhase = ''
       ./configure -installdir $out/lib/ocaml/${ocaml.version}/site-lib
     '';
  -  preInstall = "mkdir -p $out/lib/ocaml/${ocaml.version}/site-lib";
  +  createFindlibDestdir = true;
   
     meta = with stdenv.lib; {
       description = "Fast, arbitrary precision OCaml integers";
  
positive.code: let source =
    if stdenv.lib.versionAtLeast ocaml.version "4.02"
    then {
      version = "1.7";
      url = https://github.com/ocaml/Zarith/archive/release-1.7.tar.gz;
      sha256 = "0fmblap5nsbqq0dab63d6b7lsxpc3snkgz7jfldi2qa4s1kbnhfn";
    } else {
      version = "1.3";
      url = http://forge.ocamlcore.org/frs/download.php/1471/zarith-1.3.tgz;
  
negative.code: { stdenv, fetchurl
  , ocaml, findlib, pkgconfig, perl
  , gmp
  }:
  