anchor.diff:  
     installPhase = ''
       install -D i2pd $out/bin/i2pd
  +    install --mode=444 -D 'contrib/i2pd.service' "$out/etc/systemd/system/i2pd.service"
  +    installManPage 'debian/i2pd.1'
     '';
   
     meta = with lib; {
  
positive.code:   buildInputs = with lib; [ boost zlib openssl ]
      ++ optional upnpSupport miniupnpc;
  
    makeFlags =
      let ynf = a: b: a + "=" + (if b then "yes" else "no"); in
      [ (ynf "USE_AESNI" aesniSupport)
  
negative.code: { lib, stdenv, fetchFromGitHub
  , installShellFiles
  , boost, zlib, openssl
  , upnpSupport ? true, miniupnpc ? null
  , aesniSupport ? stdenv.hostPlatform.aesSupport
  