anchor.diff:    '';
   
     doInstallCheck = with stdenv; hostPlatform == buildPlatform;
  -  installCheckInputs = [ cmocka which cacert lua.cqueues lua.basexx ];
  +  installCheckInputs = [ cmocka which cacert lua.cqueues lua.basexx lua.http ];
     installCheckPhase = ''
       meson test --print-errorlogs
     '';
  
positive.code: 
  result = if extraFeatures then wrapped-full else unwrapped;
  
  inherit (stdenv.lib) optional optionals;
  lua = luajitPackages;
  
  unwrapped = stdenv.mkDerivation rec {
  
negative.code:   # http://knot-resolver.readthedocs.io/en/latest/build.html#requirements
    buildInputs = [ knot-dns lua.lua libuv gnutls lmdb ]
      ++ optional stdenv.isLinux systemd # passing sockets, sd_notify
      ++ [ nghttp2 ]
      ## optional dependencies; TODO: libedit, dnstap
      ;
  
  