anchor.diff:  
     postPatch = ''
       patchShebangs tests
  -    ${stdenv.lib.optionalString enablePython ''
  -      patchShebangs ./python/pycryptsetup-test.py
  -    ''}
   
       # O_DIRECT is filesystem dependent and fails in a sandbox (on tmpfs)
       # and on several filesystem types (btrfs, zfs) without sandboxing.
  
positive.code: { stdenv, fetchurl, lvm2, json_c
  , openssl, libuuid, pkgconfig, popt
  , enablePython ? false, python2 ? null }:
  
  assert enablePython -> python2 != null;
  
  stdenv.mkDerivation rec {
    name = "cryptsetup-2.1.0";
  
    outputs = [ "out" "dev" "man" ];
  
    src = fetchurl {
      url = "mirror://kernel/linux/utils/cryptsetup/v2.1/${name}.tar.xz";
      sha256 = "15y8n547garz0x5kqv09gscdsrz0c0y1y6c5cp8pccwg3xsb5vm3";
    };
  
    # Disable 4 test cases that fail in a sandbox
  
negative.code:   configureFlags = [
      "--enable-cryptsetup-reencrypt"
      "--with-crypto_backend=openssl"
    ];
  
    nativeBuildInputs = [ pkgconfig ];
    buildInputs = [ lvm2 json_c openssl libuuid popt ];
  
    doCheck = true;
  
  