Constraints for CPU features?

Hi. Would it be possible to detect CPU features using something
like https://github.com/google/cpu_features/
and provide them as platform constraints?

This could help in enabling certain compiler flags and instruction set
architectures for targets.

What needs to be done so that something like this would work
with Bazel?

Start by reviewing the repository's existing platform constraints and Bazel's platform and toolchain documentation. Investigate how CPU features from the proposed cpu_features project could become constraints and affect compiler flags or instruction-set targets. Done would require a decided design and an agreed implementation scope.

Written by the indexing model from the issue text.