Warning mismatches on tensorflow macos

[stellaraccident]

2021-01-12T11:06:17.7726980Z �[1mexternal/org_tensorflow/tensorflow/compiler/mlir/tensorflow/ir/tf_traits.h:91:20: �[0m�[0;1;31merror: �[0m�[1mloop variable 'operand_type' is always a copy because the range of type 'mlir::Operation::operand_type_range' (aka 'ValueTypeRange<mlir::OperandRange>') does not return a reference [-Werror,-Wrange-loop-analysis]�[0m
2021-01-12T11:06:17.7729510Z   for (const auto& operand_type : op->getOperandTypes()) {
2021-01-12T11:06:17.7735430Z �[0;1;32m                   ^
2021-01-12T11:06:17.7737130Z �[0m�[1mexternal/org_tensorflow/tensorflow/compiler/mlir/tensorflow/ir/tf_traits.h:91:8: �[0m�[0;1;30mnote: �[0muse non-reference type 'mlir::Type'�[0m
2021-01-12T11:06:17.7738980Z   for (const auto& operand_type : op->getOperandTypes()) {
2021-01-12T11:06:17.7740020Z �[0;1;32m       ^~~~~~~~~~~~~~~~~~~~~~~~~~
2021-01-12T11:06:17.7740760Z �[0m2 errors generated.

2021-01-12T11:06:17.7716040Z �[1mexternal/org_tensorflow/tensorflow/core/framework/type_index.h:61:17: �[0m�[0;1;31merror: �[0m�[1munused variable 'hash_bit' [-Werror,-Wunused-variable]�[0m
2021-01-12T11:06:17.7717460Z     static bool hash_bit[1];
2021-01-12T11:06:17.7718690Z �[0;1;32m             

I am considering just not making warnings errors for tensorflow on macos. I just don't think there is a lot of value in traipsing down these issues in someone else's project.

[GMNGeoffrey]

I think this would be fixed by #9306 as well

[ScottTodd]

Obsolete - we no longer build TensorFlow from C++ sources.