[C++] protobuf 3.7 defines EXPECT_OK that clashes with Arrow's macro

/home/travis/build/xhochy/arrow/cpp/src/arrow/flight/test-util.cc
In file included from /home/travis/build/xhochy/arrow/cpp-toolchain/include/google/protobuf/util/type_resolver.h:39:0,
                 from /home/travis/build/xhochy/arrow/cpp-toolchain/include/google/protobuf/util/json_util.h:37,
                 from /home/travis/build/xhochy/arrow/cpp-toolchain/include/grpcpp/impl/codegen/config_protobuf.h:70,
                 from /home/travis/build/xhochy/arrow/cpp/src/arrow/flight/customize_protobuf.h:23,
                 from /home/travis/build/xhochy/arrow/cpp/src/arrow/flight/protocol-internal.h:20,
                 from /home/travis/build/xhochy/arrow/cpp/src/arrow/flight/internal.h:23,
                 from /home/travis/build/xhochy/arrow/cpp/src/arrow/flight/test-util.cc:35:
/home/travis/build/xhochy/arrow/cpp-toolchain/include/google/protobuf/stubs/status.h:111:0: error: "EXPECT_OK" redefined [-Werror]
 #define EXPECT_OK(value) EXPECT_TRUE((value).ok())
 
In file included from /home/travis/build/xhochy/arrow/cpp/src/arrow/ipc/test-common.h:35:0,
                 from /home/travis/build/xhochy/arrow/cpp/src/arrow/flight/test-util.cc:30:
/home/travis/build/xhochy/arrow/cpp/src/arrow/testing/gtest_util.h:80:0: note: this is the location of the previous definition
 #define EXPECT_OK(expr)         \
 
cc1plus: all warnings being treated as errors