anchor.diff: -{ stdenv, lib, fetchurl, autoreconfHook, pkgconfig
  +{ stdenv, lib, fetchurl, fetchFromGitHub, autoreconfHook, pkgconfig
   , openssl, netcat-gnu, gnutls, gsasl, libidn, Security
  -, systemd ? null }:
  +, systemd ? null, eject ? null }:
   
   let
     tester = "n"; # {x| |p|P|n|s}
     journal = if stdenv.isLinux then "y" else "n";
  +
  +  # preferNonBlock = stdenv.isLinux;
  +  preferNonBlock = false;
  +
  +  nonblock = fetchFromGitHub {
  +    owner  = "Stebalien";
  +    repo   = "msmtp-queue";
  +    rev    = "07032a4e4c8ea0d2364641c959db0c60f52423c7";
  +    sha256 = "0g2aph30007spkdwxljrlr2bliivf9nrdis3d3jvjpx8l6k60rr9";
  +  };
   
   in stdenv.mkDerivation rec {
     name = "msmtp-${version}";
  
positive.code: 
      substitute scripts/msmtpq/msmtp-queue $out/bin/msmtp-queue \
        --replace @msmtpq@ $out/bin/msmtpq
  
      chmod +x $out/bin/*
    '';
  
negative.code:   ];
  
    buildInputs = [ openssl gnutls gsasl libidn ]
      ++ lib.optional stdenv.isDarwin Security
      ++ lib.optionals preferNonBlock [ nonblock eject ];
    nativeBuildInputs = [ autoreconfHook pkgconfig ];
  
    enableParallelBuilding = true;
  
    configureFlags =
      stdenv.lib.optional stdenv.isDarwin [ "--with-macosx-keyring" ];
  
    postInstall = ''
      ${lib.optionalString (!preferNonBlock) ''
      substitute scripts/msmtpq/msmtpq $out/bin/msmtpq \
        --replace @msmtp@      $out/bin/msmtp \
        --replace @nc@         ${netcat-gnu}/bin/nc \
  