protobuf: add 3.0.0b2

For tensorflow

pkgs/development/libraries/protobuf/3.0.0-beta-2.nix

@@ -0,0 +1,43 @@
+{ stdenv, fetchFromGitHub , autoreconfHook, zlib, gmock }:
+
+stdenv.mkDerivation rec {
+  name = "protobuf-${version}";
+
+  version = "3.0.0-beta-2";
+  # make sure you test also -A pythonPackages.protobuf
+  src = fetchFromGitHub {
+    owner = "google";
+    repo = "protobuf";
+    rev = "v${version}";
+    sha256 = "0cbr1glgma5vakabsjwcs41pcnn8yphhn037l0zd121zb9gdaqc1";
+  };
+
+  postPatch = ''
+    rm -rf gmock
+    cp -r ${gmock.source} gmock
+    chmod -R a+w gmock
+  '' + stdenv.lib.optionalString stdenv.isDarwin ''
+    substituteInPlace src/google/protobuf/testing/googletest.cc \
+      --replace 'tmpnam(b)' '"'$TMPDIR'/foo"'
+  '';
+
+  buildInputs = [ autoreconfHook zlib ];
+
+  enableParallelBuilding = true;
+
+  doCheck = true;
+
+  meta = {
+    description = "Google's data interchange format";
+    longDescription =
+      ''Protocol Buffers are a way of encoding structured data in an efficient
+        yet extensible format. Google uses Protocol Buffers for almost all of
+        its internal RPC protocols and file formats.
+      '';
+    license = stdenv.lib.licenses.bsd3;
+    platforms = stdenv.lib.platforms.unix;
+    homepage = https://developers.google.com/protocol-buffers/;
+  };
+
+  passthru.version = version;
+}

pkgs/top-level/all-packages.nix

@@ -9081,6 +9081,8 @@ in
 
   protobuf = protobuf2_6;
   protobuf3_0 = lowPrio (callPackage ../development/libraries/protobuf/3.0.nix { });
+  # 3.0.0-beta-2 is only introduced for tensorflow. remove this version when tensorflow is moved to 3.0.
+  protobuf3_0_0b2 = lowPrio (callPackage ../development/libraries/protobuf/3.0.0-beta-2.nix { });
   protobuf2_6 = callPackage ../development/libraries/protobuf/2.6.nix { };
   protobuf2_5 = callPackage ../development/libraries/protobuf/2.5.nix { };