anchor.diff:      sed -i 's,/usr/bin/env python,'$(type -P python), \
         $(find contrib -type f)
       mkdir -p $out/share/cjdns
  -    cp -R contrib node_build node_modules $out/share/cjdns/
  +    cp -R contrib tools node_build node_modules $out/share/cjdns/
     '';
   
     meta = with stdenv.lib; {
  
positive.code:   src = fetchFromGitHub {
      owner = "cjdelisle";
      repo = "cjdns";
      rev = "97161a5fef6b98ffbba94888587bd9ce733c2278";
      sha256 = "0wxiwgjcl4rn71b6hjdlfgv9hjy9d43sypikzcl5z65r7xkrb41j";
    };
  
    buildInputs = [ which python27 nodejs ] ++
  
negative.code: 
  let
    version = "15"; # see ${src}/util/version/Version.h
    date = "20150130";
  in
  stdenv.mkDerivation {
    name = "cjdns-${version}-${date}";
  