anchor.diff:      # the linux-like directory structure is used for proper output splitting
       "-DOSX_PACKAGE=off"
       "-DOSX_FRAMEWORK=off"
  +  ] ++ lib.optionals (!avahiSupport) [
  +    "-DHAVE_DNS_SD=OFF"
     ];
   
     postPatch = ''
  
positive.code: , libxml2
  , python
  , libusb1
  , avahi
  , libaio
  , runtimeShell
  , lib
  
negative.code:     python
      libxml2
      libusb1
    ] ++ lib.optional python.isPy3k python.pkgs.setuptools
      ++ lib.optional avahiSupport avahi
      ++ lib.optional stdenv.isLinux libaio
      ++ lib.optionals stdenv.isDarwin [ CFNetwork CoreServices ];
  
  