anchor.diff: -{ stdenv, lib, fetchFromGitHub, cmake, pkg-config
  +{ stdenv, lib, fetchFromGitHub, cmake, pkg-config, darwin
   , alsa-lib, asio, avahi, boost17x, flac, libogg, libvorbis, soxr
   , aixlog, popl
   , pulseaudioSupport ? false, libpulseaudio
  
positive.code:     description = "Synchronous multi-room audio player";
      homepage = "https://github.com/badaix/snapcast";
      maintainers = with maintainers; [ fpletz ];
      license = licenses.gpl3Plus;
    };
  }
  
negative.code:   # not needed
    buildInputs = [
      boost17x
      asio avahi flac libogg libvorbis
      aixlog popl soxr
    ] ++ lib.optional pulseaudioSupport libpulseaudio
    ++ lib.optional stdenv.isLinux alsa-lib
    ++ lib.optional stdenv.isDarwin [darwin.apple_sdk.frameworks.IOKit darwin.apple_sdk.frameworks.AudioToolbox];
  
    TARGET=lib.optionalString stdenv.isDarwin "MACOS";
  
    # Upstream systemd unit files are pretty awful, so we provide our own in a
    # NixOS module. It might make sense to get that upstreamed...
  