added c++17 flag

[chinmayshah99]

Description

After the latest code push by google, they started using c++17 which caused our code to break. Fixed that process.

Fixes # (issue)

Partial issue #

Type of change

Please mark options that are relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Did you run make test-all?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• bazel build successful
• Test B

Checklist:

• New Unit tests added
• Unit tests pass locally with my changes

[replomancer]

This change doesn't fix #144 on Ubuntu 20.04. I get the same error messages as before.

[chinmayshah99]

I mentioned it as Partial fix since I suspected maybe adding c++17 will do away with some errors. But seems like it doesn't.

Without adding c++17 flag, I was not able to build the code on my Ubuntu 18.04 system.