anchor.diff:  
     buildInputs = [
       libcap
  -    libgcrypt
       libidn
  -    nettle
       openssl
       spCompat
     ];
  
positive.code:   '' +
    /* iputils does not provide a make install target */ ''
      install -vDm 755 ping $out/bin/ping
      install -vDm 755 ping6 $out/bin/ping6
      install -vDm 755 tracepath $out/bin/tracepath
      install -vDm 755 tracepath6 $out/bin/tracepath6
      install -vDm 755 clockdiff $out/bin/clockdiff
      install -vDm 755 arping $out/bin/arping
      install -vDm 755 rdisc $out/bin/rdisc
      install -vDm 755 ninfod/ninfod $out/bin/ninfod
      install -vDm 755 tracepath $out/bin/tracepath
      install -vDm 755 tracepath $out/bin/tracepath
  
      install -vDm 644 doc/clockdiff.8 $out/share/man/man8/clockdiff.8
      install -vDm 644 doc/arping.8 $out/share/man/man8/arping.8
      install -vDm 644 doc/ping.8 $out/share/man/man8/ping.8
      install -vDm 644 doc/rdisc.8 $out/share/man/man8/rdisc.8
      install -vDm 644 doc/tracepath.8 $out/share/man/man8/tracepath.8
      install -vDm 644 doc/ninfod.8 $out/share/man/man8/ninfod.8
      ln -s $out/share/man/man8/{ping,ping6}.8
      ln -s $out/share/man/man8/{tracepath,tracepath6}.8
    '' + ''
      runHook 'postInstall'
    '';
  
negative.code: { stdenv
  , docbook_sgml_dtd_31
  , fetchFromGitHub
  , perlPackages
  
  , libcap
  , libidn
  , openssl
  , spCompat
  }:
  
  let
  in
  stdenv.mkDerivation rec {
    name = "iputils-2016-08-04";
  
    src = fetchFromGitHub {
      owner = "iputils";
      repo = "iputils";
      rev = "3c7b5f7177b62245babe42e1e5b572865186ab7b";
      sha256 = "a2859de8ed13d7d189551cfec8248587bc33ab5e22e498c3b9ed6a5c82e0e7cf";
    };
  
    postPatch =
    /* Fix expected filename */ ''
  