anchor.diff:  
     src = fetchurl {
       url = "https://www.open-mpi.org/software/hwloc/v${versmm}/downloads/${name}.tar.bz2";
  -    sha256 = "0qh8s7pphz0m5cwb7liqmc17xzfs23xhz5wn24r6ikvjyx99fhhr";
  +    sha256 = "0li27a3lnmb77qxpijj0kpblz32wmqd3b386sypq8ar7vy9vhw5f";
     };
   
     configureFlags = [
  
positive.code: with stdenv.lib;
  
  let
    version = "2.1.0";
    versmm = versions.major version + "." + versions.minor version;
    name = "hwloc-${version}";
  
  
negative.code: 
      # https://www.open-mpi.org/projects/hwloc/license.php
      license = licenses.bsd3;
      homepage = "https://www.open-mpi.org/projects/hwloc/";
      maintainers = with maintainers; [ fpletz markuskowa ];
      platforms = platforms.all;
    };
  