anchor.diff:  
     mlPlugin = true;
   
  -  buildPhase = "make build";
  -
     installFlags = [ "DESTDIR=$(out)" "COQMF_COQLIB=lib/coq/${coq.coq-version}" ];
     extraInstallFlags = [ "VFILES=structures.v" ];
   
  
positive.code: { lib, mkCoqDerivation, which, coq, coq-elpi, version ? null }:
  
  with lib; mkCoqDerivation {
    pname = "hierarchy-builder";
    owner = "math-comp";
    inherit version;
  
negative.code:     maintainers = with maintainers; [ cohencyril siraben ];
      license = licenses.mit;
    };
  }; in
  hb.overrideAttrs (o:
    optionalAttrs (versions.isGe "1.2.0" o.version || o.version == "dev")
      { buildPhase = "make build"; }
  )
  