anchor.diff:  
     NIX_CFLAGS_COMPILE = "-DAVAHI_SERVICE_DIR=\"/etc/avahi/services\"";
   
  -  prePatch = ''
  -    substituteInPlace configure \
  -      --replace pkg-config "$PKG_CONFIG"
  -  '';
  -
     preBuild = lib.optionalString stdenv.isDarwin ''
       sed -i '20 i\
       #define __APPLE_USE_RFC_2292' \
  
positive.code:     })
    ];
  
    nativeBuildInputs = [
      pkg-config
      pkg-config-helper
      gettext
      glib
    ];
  
negative.code: 
  assert qt4Support -> qt4 != null;
  
  stdenv.mkDerivation rec {
    pname = "avahi${lib.optionalString withLibdnssdCompat "-compat"}";
    version = "0.8";
  