anchor.diff:      make -f Makefile.coq COQLIB=$out/lib/coq/${coq.coq-version}/ install
     '';
   
  -  meta = with stdenv.lib ; {
  +  meta = with stdenv.lib; {
       homepage = http://color.inria.fr/;
       description = "CoLoR is a library of formal mathematical definitions and proofs of theorems on rewriting theory and termination whose correctness has been mechanically checked by the Coq proof assistant.";
       maintainers = with maintainers; [ jpas jwiegley ];
  
positive.code: { stdenv, fetchFromGitHub, coq, bignums }:
  
  stdenv.mkDerivation {
    name = "coq${coq.coq-version}-CoLoR-1.6.0";
  
    src = fetchFromGitHub {
      owner = "fblanqui";
      repo = "color";
      rev = "328aa06270584b578edc0d2925e773cced4f14c8";
      sha256 = "07sy9kw1qlynsqy251adgi8b3hghrc9xxl2rid6c82mxfsp329sd";
    };
  
    buildInputs = [ coq bignums ];
  
negative.code:   };
  
    passthru = {
      compatibleCoqVersions = v: builtins.hasAttr v coqVersions;
    };
  }
  