anchor.diff:  , withALSA ? true, alsaLib ? null
   , withPulseAudio ? false, libpulseaudio ? null
   , withPortAudio ? false, portaudio ? null
  +, withMpris ? false
  +, withKeyring ? false
  +, dbus ? null
   }:
   
   rustPlatform.buildRustPackage rec {
  
positive.code:   cargoBuildFlags = [
      "--no-default-features"
      "--features"
      "${stdenv.lib.optionalString withALSA "alsa_backend,"}${stdenv.lib.optionalString withPulseAudio "pulseaudio_backend,"}${stdenv.lib.optionalString withPortAudio "portaudio_backend,"}"
    ];
  
    nativeBuildInputs = [ pkgconfig ];
  
negative.code:   buildInputs = [ openssl ]
      ++ stdenv.lib.optional withALSA alsaLib
      ++ stdenv.lib.optional withPulseAudio libpulseaudio
      ++ stdenv.lib.optional withPortAudio portaudio
      ++ stdenv.lib.optional (withMpris || withKeyring) dbus;
  
    doCheck = false;
  
  