anchor.diff:  
     tail = buildFromGitHub {
       version = 3;
  -    rev = "a927b6857fc77f4823ab37102e948be667b92bd8";
  +    rev = "66928beff07e654d08f02f592e53aaab8df488d5";
       owner  = "hpcloud";
       repo   = "tail";
  -    sha256 = "0hldmklvcyz2scnil5arbpyz7l3djkgmdvv3lg09sq1ajky6bv9r";
  +    sha256 = "0llv0iaa2pc7pkvccj0lx3by7kmikkf8y13xa1xl9s96p24sxwqd";
       propagatedBuildInputs = [
         fsnotify_v1
         tomb_v1
       ];
  -    date = "2017-07-07";
  +    date = "2017-08-03";
     };
   
     tar-split = buildFromGitHub {
  
positive.code: 
    tools = buildFromGitHub {
      version = 3;
      rev = "4e70a1b26a7875f00ca1916637a876b5ffaeec59";
      date = "2017-08-02";
      owner = "golang";
      repo = "tools";
      sha256 = "1qvxcis0pavid53myg6nf6f4qnl6vq5qnc0m9kjf8zgg7bwg18bm";
      goPackagePath = "golang.org/x/tools";
  
      preConfigure = ''
  
negative.code: 
    syncthing = buildFromGitHub rec {
      version = 3;
      rev = "v0.14.34";
      owner = "syncthing";
      repo = "syncthing";
      sha256 = "1p5i389kmxki10qifdk6pl8i9imxk98dr6nbv6ly4kfz7z5akcif";
      buildFlags = [ "-tags noupgrade" ];
      buildInputs = [
        AudriusButkevicius_cli
  