anchor.diff:      version = 2;
       owner = "coreos";
       repo = "etcd";
  -    date = "2017-04-21";
  -    rev = "a9087ee659e58f26de72c4809ddabd8f58b4a97a";
  -    sha256 = "1qjm9blr6lhbbaxwrahb434a4s6kjda1c8c1p1s8nqj2hlz6jsm4";
  +    rev = "v3.1.6";
  +    sha256 = "12024ccvyln5v4b9xab3yd8hjgzbh576ky934k9kqx78mzqcmvsp";
       buildInputs = [
         bolt
         btree
         urfave_cli
  +      ccache
         clockwork
         cobra
         cmux
  +      crypto
         go-grpc-prometheus
         go-humanize
         go-semver
         go-systemd
  -      gopcap
  -      groupcache
         grpc
         grpc-gateway
  -      loghisto
         net
         pb_v1
         pflag
         pkg
         probing
  -      procfs
         prometheus_client_golang
  +      protobuf
  +      gogo_protobuf
         pty
  -      gogo_protobuf
         speakeasy
         tablewriter
         time
  
positive.code: 
        pkgs.libpcap
      ];
      meta.useUnstable = true;
    };
  
    etcd_client = buildFromGitHub {
      inherit (etcd) rev date owner repo sha256 version meta;
      subPackages = [
        "client"
        "pkg/fileutil"
  
negative.code:     owner = "couchbase";
      repo = "cbauth";
      sha256 = "185c10ab80cn4jxdp915h428lm0r9zf1cqrfsjs71im3w3ankvsn";
    };
  
    ccache = buildFromGitHub {
      version = 2;
      rev = "v2.0.2";
      owner = "karlseguin";
      repo = "ccache";
      sha256 = "11zg85f5v89dfqy1s5xs42cs56sxdqs768l9wx73yksxqkidddbh";
    };
  
    certificate-transparency = buildFromGitHub {
  