pytorch

606b2343 - turn on -Werror=unused-function in our Bazel CPU build

turn on -Werror=unused-function in our Bazel CPU build Summary: We also fix any existing issues. Note that we only do this for the CPU build because nvcc is considered a C++ toolchain but it does not have the same flag support. Adding flags to the GPU build will cause nvcc errors. Test Plan: Built locally, rely on CI to confirm. Reviewers: malfet Subscribers: Tasks: Tags: Pull Request resolved: https://github.com/pytorch/pytorch/pull/79154 Approved by: https://github.com/seemethere, https://github.com/osalpekar, https://github.com/albanD