anchor.diff:        outputs = [ "out" "doc" "man" ];
   
         mesonFlags = [
  -        # Documentation is enabled unconditionally but it's not installed
  -        # unconditionally thanks to the outputs being split
  -        "-Ddocumentation=true"
           "-Dtest=true"
  +        "-Dmanpages=true"
  +        "-Dhtml_manual=true"
         ]
           ++ map (x: "-D${x}=enabled") features_
           ++ map (x: "-D${x}=disabled") (lib.subtractLists features_ knownFeatures)
  
positive.code: 
  let
    lib = stdenv.lib;
  
    featureDependencies = {
      # Storage plugins
  
negative.code: 
      in stdenv.mkDerivation rec {
        pname = "mpd";
        version = "0.22";
  
        src = fetchFromGitHub {
          owner  = "MusicPlayerDaemon";
          repo   = "MPD";
          rev    = "v${version}";
          sha256 = "1lsi4fgrarabkahfhf5zbmppg7jba7m362gxyqhv54hmqprl1qff";
        };
  
        buildInputs = [
  