Add missing public headers
diff --git a/build.json b/build.json
index b45584a..0a7b81d 100644
--- a/build.json
+++ b/build.json
@@ -29,6 +29,12 @@
         "include/grpc++/impl/rpc_method.h",
         "include/grpc++/impl/rpc_service_method.h",
         "include/grpc++/impl/service_type.h",
+        "include/grpc++/impl/sync.h",
+        "include/grpc++/impl/sync_cxx11.h",
+        "include/grpc++/impl/sync_no_cxx11.h",
+        "include/grpc++/impl/thd.h",
+        "include/grpc++/impl/thd_cxx11.h",
+        "include/grpc++/impl/thd_no_cxx11.h",
         "include/grpc++/server.h",
         "include/grpc++/server_builder.h",
         "include/grpc++/server_context.h",