anchor.diff:  
       excludedPackages = "\\(test\\|benchmark\\|example\\|bridge\\)";
       meta.useUnstable = true;
  -    date = "2018-04-20";
  +    date = "2018-05-02";
     };
   
     etcd_client = etcd.override {
  
positive.code:       popd >/dev/null
        export CGO_CPPFLAGS="-I$srcdir/src/daemon -I$srcdir/src"
      '';
      date = "2017-04-11";
    };
  
    go-colorable = buildFromGitHub {
  
negative.code:   };
  
    go-discover = buildFromGitHub {
      version = 6;
      rev = "c7c0eb3fc6b6f8024c39cb24f3fe254a72595dd4";
      owner  = "hashicorp";
      repo   = "go-discover";
      sha256 = "07k718i726iay78y9k7nlyx1i3ki2szyj184z7wk4lb8g6y4zn3x";
      date = "2018-04-27";
      propagatedBuildInputs = [
        aliyungo
        aws-sdk-go
  