anchor.diff:      "--enable-wave-encoder"
       "--${boolEn (wavpack != null)}-wavpack"
       "--${boolWt (avahi != null && dbus != null)}-zeroconf${
  -        boolString (avahi != null && dbus != null) "avahi" ""}"
  +        boolString (avahi != null && dbus != null) "=avahi" ""}"
       "--${boolEn (zlib != null)}-zlib"
       "--${boolEn (zziplib != null)}-zzip"
       "--${boolWt (systemd_lib != null)}-systemdsystemunitdir${
  -        boolString (systemd_lib != null) "$(out)/etc/systemd/system" ""}"
  +        boolString (systemd_lib != null) "=$(out)/etc/systemd/system" ""}"
       "--disable-debug"
       "--${boolEn documentationSupport}-documentation"
       "--disable-werror"
  
positive.code:   ];
  
    configureFlags = [
      "--help"
      "--disable-aac"
      # TODO: adplug support
      #"--${boolEn }-adplug" true null)
  
negative.code: let
    inherit (stdenv.lib)
      boolEn
      boolString
      boolWt
      optional
      optionals;
  