anchor.diff:  
     prometheus_common = buildFromGitHub {
       version = 2;
  -    date = "2017-02-20";
  -    rev = "49fee292b27bfff7f354ee0f64e1bc4850462edf";
  +    date = "2017-04-18";
  +    rev = "9e0844febd9e2856f839c9cb974fbd676d1755a8";
       owner = "prometheus";
       repo = "common";
  -    sha256 = "03b452lj2cig2ar2ml6giqlqvjg4qbizmxzrdqclil9308d5d2c5";
  +    sha256 = "1nyrwbciin136836dz7g18wr6zzs63kwm39c56is6aapm4im3mik";
       buildInputs = [
         logrus
         net
  
positive.code:       tar-utils
      ];
      meta.useUnstable = true;
      date = "2017-03-06";
    };
  
    go-ipfs-util = buildFromGitHub {
  
negative.code: 
    speakeasy = buildFromGitHub {
      version = 2;
      date = "2017-04-17";
      rev = "4aabc24848ce5fd31929f7d1e4ea74d3709c14cd";
      owner = "bgentry";
      repo = "speakeasy";
      sha256 = "05w4vlyglkzgwhfp2ini4yd3l8zblpx8b5sfsy649hzh8mm5v68p";
    };
  
    srslog = buildFromGitHub {
  