This fixes a memory corruption vulnerability for anyone using cord with dynamically built descriptor pools.

    * Move -Werror to our test/dev bazelrc files.

    Putting it into BUILD files unintentionally forces it on all our downstream users.  Instead, we just want to enable this during testing and let them choose for themselves in their builds.

    Note, that this expands the scope of -Werror to our entire repo for CI, so a bunch of fixes and opt-outs had to be applied to get this change passing.

    Closed #14714

    PiperOrigin-RevId: 666903224

    * Fix extra warnings on 28.x

    * Fix zlib issues on macos

    * Second try at zlib/macos issues

    * Only disable deprecated-non-prototype on macos-14