anchor.diff:    ];
   
     buildInputs = [ openssl gnutls gsasl libidn ]
  -    ++ stdenv.lib.optional stdenv.isDarwin Security;
  +    ++ 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 \
  
positive.code: { stdenv, lib, fetchurl, autoreconfHook, pkgconfig
  , openssl, netcat-gnu, gnutls, gsasl, libidn, Security
  , systemd ? null }:
  
  let
    tester = "n"; # {x| |p|P|n|s}
    journal = if stdenv.isLinux then "y" else "n";
  
  in stdenv.mkDerivation rec {
    name = "msmtp-${version}";
  
negative.code: 
      substitute scripts/msmtpq/msmtp-queue $out/bin/msmtp-queue \
        --replace @msmtpq@ $out/bin/msmtpq
      ''}
      ${lib.optionalString preferNonBlock ''
      mkdir -p $out/lib/systemd/user
      cp ${nonblock}/msmtp* $out/bin/
      cp ${nonblock}/systemd/* $out/lib/systemd/user
      for f in $out/bin/msmtpq* ; do
        sed $f -i -r \
          -e 's|^QUEUE_DIR.*|QUEUE_DIR="''${MSMTP_QUEUE:-''${XDG_DATA_HOME:-$HOME/.local/share}/mail.queue}"|' \
          -e 's|^CONFIG.*|CONFIG="''${XDG_CONFIG_HOME:-$HOME/.config}/msmtprc"|' \
          -e 's| flock | ${eject}/bin/flock |'
      done
      for f in $out/lib/systemd/user/* ; do
        substituteInPlace $f \
          --replace /usr/local               $out \
          --replace .local/share/mail.queue  .cache/msmtp/queue
      done
      ''}
  
      chmod +x $out/bin/*
    '';
  