Create compiler constraint setting

[hlopko]

This is a tracking issue for adding compiler constraint setting.

Blockers:

• [x] https://github.com/bazelbuild/bazel/issues/8763
• [ ] https://github.com/bazelbuild/bazel/issues/8766

Steps:

• [ ] Add constraint_setting into rules_cc repo
• [ ] Hook into Bazel's host platform detection
• [ ] Make cc_configure populate the compiler constraint in its toolchains