anchor.diff:  
     protobuf = buildFromGitHub {
       version = 2;
  -    rev = "8ee79997227bf9b34611aee7946ae64735e6fd93";
  -    date = "2016-11-16";
  +    rev = "69b215d01a5606c843240eab4937eab3acee6530";
  +    date = "2017-02-17";
       owner = "golang";
       repo = "protobuf";
  -    sha256 = "12x7d1m6ryjqj4a1hvg60pgx12acvvc8997zlwfzzzmnb6dbc83q";
  +    sha256 = "0j2gnjmgzdwnh71fl5clwrkwpvq01rg8jz267d7ppsmbgfalmjlk";
       goPackagePath = "github.com/golang/protobuf";
       goPackageAliases = [
         "code.google.com/p/goprotobuf"
  
positive.code:     version = 2;
      owner = "spf13";
      repo = "viper";
      rev = "5ed0fc31f7f453625df314d8e66b9791e8d13003";
      date = "2016-12-13";
      sha256 = "06811p1sbs3157ci7jjxq48gx0mzyiaawacc9spq01k9sv42zm7l";
      buildInputs = [
        crypt
        pflag
  
negative.code:       procfs
        beorn7_perks
      ];
      date = "2017-02-17";
    };
  
    prometheus_client_model = buildFromGitHub {
      version = 2;
      rev = "6f3806018612930941127f2a7c6c453ba2c527d2";
      date = "2017-02-16";
      owner  = "prometheus";
      repo   = "client_model";
      sha256 = "0a9i3ja3pp6sj2v2qshnp12mdgshngwf73p0jmmhn2yddipbngc0";
      buildInputs = [
        protobuf
      ];
  