anchor.diff:  
   
     protobuf = buildFromGitHub {
  -    rev = "59b73b37c1e45995477aae817e4a653c89a858db";
  -    date = "2015-08-23";
  +    rev = "68415e7123da32b07eab49c96d2c4d6158360e9b";
  +    date = "2015-12-06";
       owner = "golang";
       repo = "protobuf";
  -    sha256 = "1dx22jvhvj34ivpr7gw01fncg9yyx35mbpal4mpgnqka7ajmgjsa";
  +    sha256 = "0gi2r9n7fbr7vz0rkvngnrc1y0bbk1zyqlph023s76w8d98ykxx2";
       goPackagePath = "github.com/golang/protobuf";
       goPackageAliases = [ "code.google.com/p/goprotobuf" ];
     };
  
positive.code:   };
  
    oauth2 = buildFromGitHub {
      rev = "397fe7649477ff2e8ced8fc0b2696f781e53745a";
      date = "2015-06-23";
      owner = "golang";
      repo = "oauth2";
      sha256 = "0fza0l7iwh6llkq2yzqn7dxi138vab0da64lnghfj1p71fprjzn8";
      goPackagePath = "golang.org/x/oauth2";
      goPackageAliases = [ "github.com/golang/oauth2" ];
      propagatedBuildInputs = [ net gcloud-golang-compute-metadata ];
  
negative.code:   };
  
    sys = buildFromGitHub {
      rev    = "2bacc619e34d59719d9ed86f0e04e8261aed3409";
      date   = "2015-11-24";
      owner  = "golang";
      repo   = "sys";
      sha256 = "1wz735axs221jcdr7qbmm72vkkhngsl2zcaz0d4n2f721cbhb1bq";
      goPackagePath = "golang.org/x/sys";
      goPackageAliases = [
        "github.com/golang/sys"
  