anchor.diff:  
     image-spec = buildFromGitHub {
       version = 3;
  -    rev = "d207df434d113728dc3373cb3a905f00b482a858";
  +    rev = "af173bcb2fb0e0b95f240b914c4791f69738b765";
       owner  = "opencontainers";
       repo   = "image-spec";
  -    sha256 = "16icx57ppmlmdrdzsf6y3zad3hdznmlzp5zsm5mm97cyigs6746f";
  -    date = "2017-06-16";
  +    sha256 = "0rpvjrg8b6amjnnr81nzvy4dqzd4szk83r9ssjw7vw80v7idv9py";
  +    date = "2017-06-23";
       propagatedBuildInputs = [
         errors
         go4
  
positive.code:   };
  
    pester = buildFromGitHub {
      version = 2;
      owner = "sethgrid";
      repo = "pester";
      rev = "4f4c0a67b6496764028e1ab9fd8dfb630282ed2f";
      date = "2017-04-08";
      sha256 = "0xydrln1gmzb9kqf0kq7g62xazsxrnza5w8g0jzppdpf25zjnxwm";
    };
  
    pfilter = buildFromGitHub {
  
negative.code:       "pkg/jsonlog"
        "pkg/jsonmessage"
        "pkg/longpath"
        "pkg/stringid"
        "pkg/tarsum"
        "pkg/term"
  