anchor.diff:      rev = "2268707a8f0843315e2004ee4f1d021dc08baedf";
       sha256 = "164ly3njl7qbd4ddh8slmphwrs7vm7k8p6l5az57qrg3w00aijfy";
       date = "2017-02-01";
  +  };
  +
  +  kcp-go = buildFromGitHub {
  +    version = 2;
  +    owner = "xtaci";
  +    repo = "kcp-go";
  +    rev = "v3.10";
  +    sha256 = "11lnk98n7988hkqsk8yy610m67ai7v2vjppfjc0k6cpda5s0qaf3";
  +    propagatedBuildInputs = [
  +      crypto
  +      errors
  +      net
  +      reedsolomon
  +    ];
     };
   
     gravitational_kingpin = buildFromGitHub {
  
positive.code:     sha256 = "0sjni0qz026xr4q04j0dzi0jnxnipm86qpic9l4wmxcf2q0bzx1y";
    };
  
    pflag = buildFromGitHub {
      version = 2;
      owner = "spf13";
  
negative.code:       go-deadlock
        go-lz4
        go-nat-pmp
        go-stun
        gogo_protobuf
        goleveldb
        groupcache
        kcp-go
        luhn
        net
        osext
        pfilter
        pq
        qart
        ql
        rcrowley_go-metrics
        rollinghash
        sha256-simd
        smux
        suture
        text
        time
  