add protobuf submodule
diff --git a/.gitmodules b/.gitmodules
index e98f319..411fab3 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -7,3 +7,6 @@
[submodule "third_party/protobuf-c"]
path = third_party/protobuf-c
url = https://github.com/protobuf-c/protobuf-c.git
+[submodule "third_party/protobuf"]
+ path = third_party/protobuf
+ url = https://github.com/google/protobuf.git
diff --git a/third_party/protobuf b/third_party/protobuf
new file mode 160000
index 0000000..703cd8e
--- /dev/null
+++ b/third_party/protobuf
@@ -0,0 +1 @@
+Subproject commit 703cd8e11c8d34283d4c8bf869c61866e8211c9d