anchor.diff:  
     sys = buildFromGitHub {
       version = 2;
  -    rev = "21f2569f6feb83b68a25c98c1b20eca5d4e1e6ae";
  -    date = "2017-02-28";
  +    rev = "76cc09b634294339fa19ec41b5f2a0b3932cea8b";
  +    date = "2017-03-01";
       owner  = "golang";
       repo   = "sys";
  -    sha256 = "07fcbvjyadzc70lbky6b4hdxkb0vhxrp41zzz4xansakd8bdq51d";
  +    sha256 = "0vn8whgr4ci43bdga8x0knii6p0r5k4afdw0zmn7iixyw1psrm6f";
       goPackagePath = "golang.org/x/sys";
       goPackageAliases = [
         "github.com/golang/sys"
  
positive.code: 
    google-cloud-go = buildFromGitHub {
      version = 2;
      date = "2017-02-28";
      rev = "5e7b3ea7ac9326eccc657cc16879281396d1b93a";
      owner = "GoogleCloudPlatform";
      repo = "google-cloud-go";
      sha256 = "1d93w5miy0k4bwsfgiwp3lml7802n9bp7cd05sjf6ccf5xhrza56";
      goPackagePath = "cloud.google.com/go";
      goPackageAliases = [
        "google.golang.org/cloud"
  
negative.code:     version = 2;
      owner = "ncw";
      repo = "rclone";
      rev = "5fba9132071b8696cb9ae595f2bf700f2ec62403";
      sha256 = "008is871bv3y55arikqpi2pvwqy2y7gpik8x4yzn0n85hr90x58b";
      propagatedBuildInputs = [
        aws-sdk-go
        cobra
  