anchor.diff:  
     snappy = buildFromGitHub {
       rev    = "0c7f8a7704bfec561913f4df52c832f094ef56f0";
  +    date   = "2015-07-21";
       owner  = "golang";
       repo   = "snappy";
       sha256 = "17j421ra8jm2da8gc0sk71g3n1nizqsfx1mapn255nvs887lqm0y";
  
positive.code:     sha256 = "1xx6lpv1r2sji8m9w35a2fkr9v4vsgvxrrahcq9bdg75qvadq91d";
    };
  
    golang_protobuf_extensions = buildGoPackage rec {
      rev = "fc2b8d3a73c4867e51861bbdd5ae3c1f0869dd6a";
      name = "golang-protobuf-extensions-${stdenv.lib.strings.substring 0 7 rev}";
      goPackagePath = "github.com/matttproud/golang_protobuf_extensions";
  
      src = fetchFromGitHub {
        inherit rev;
        owner = "matttproud";
        repo = "golang_protobuf_extensions";
        sha256 = "0ajg41h6402big484drvm72wvid1af2sffw0qkzbmpy04lq68ahj";
      };
  
      buildInputs = [ protobuf ];
    };
  
    goleveldb = buildGoPackage rec {
      rev = "e9e2c8f6d3b9c313fb4acaac5ab06285bcf30b04";
      name = "goleveldb-${stdenv.lib.strings.substring 0 7 rev}";
      goPackagePath = "github.com/syndtr/goleveldb";
      src = fetchFromGitHub {
        inherit rev;
        owner = "syndtr";
        repo = "goleveldb";
        sha256 = "0vg3pcrbdhbmanwkc5njxagi64f4k2ikfm173allcghxcjamrkwv";
      };
      propagatedBuildInputs = [ ginkgo gomega gosnappy ];
    };
  
    gollectd = buildFromGitHub {
  
negative.code:     propagatedBuildInputs = [ kr.text ];
    };
  
    prometheus.client_golang = buildFromGitHub rec {
      rev = "0.7.0";
      date = rev;  # Trick buildFromGitHub into keeping the version number
      owner = "prometheus";
      repo = "client_golang";
      sha256 = "1i3g5h2ncdb8b67742kfpid7d0a1jas1pyicglbglwngfmzhpkna";
      propagatedBuildInputs = [
        goautoneg
        protobuf
  