anchor.diff:  { stdenv, fetchurl, fetchFromGitHub, python3, python3Packages, zbar, secp256k1
  +, enableQt ? !stdenv.isDarwin
   
   
   # for updater.nix
  
positive.code: 
      # TODO plugins
      # amodem
    ];
  
    preBuild = ''
      sed -i 's,usr_share = .*,usr_share = "'$out'/share",g' setup.py
      sed -i "s|name = 'libzbar.*'|name='${zbar}/lib/libzbar.so'|" electrum/qrscanner.py
      substituteInPlace ./electrum/ecc_fast.py --replace libsecp256k1.so.0 ${secp256k1}/lib/libsecp256k1.so.0
    '';
  
    postInstall = ''
      # Despite setting usr_share above, these files are installed under
      # $out/nix ...
      mv $out/${python3.sitePackages}/nix/store"/"*/share $out
  
negative.code:     protobuf
      pyaes
      pycryptodomex
      pysocks
      qrcode
      requests
      tlslite-ng
  