HeCompile Error When compile gRPC that `‘-std=c++11’ is valid for C++/ObjC++ but not for C `

I am trying to compile grpc_python_plugin. I downloaded the latest grpc package in Github. Following the instruction, I went into the grpc directory, and start to compile with

make grpc_python_plugin

, and get the following error:

wcf@wcf-OptiPlex-7060:~/resq/grpc$ make grpc_python_plugin
[C]       Compiling third_party/address_sorting/address_sorting.c
cc1: error: command line option ‘-std=c++11’ is valid for C++/ObjC++ but not for C [-Werror]
cc1: all warnings being treated as errors
Makefile:2972: recipe for target '/home/wcf/resq/grpc/objs/opt/third_party/address_sorting/address_sorting.o' failed
make: *** [/home/wcf/resq/grpc/objs/opt/third_party/address_sorting/address_sorting.o] Error 1
wcf@wcf-OptiPlex-7060:~/resq/grpc$ error: command line option ‘-std=c++11’ is valid for C++/ObjC++ but not for C [-Werror]

Since the Makefile for grpc is so giant, I cannot find any way to solve the problem. Could you share some idea on my problem? Thank you for your time.