message: Pass `cc_opt_flags` to `host_copt`.
  For GPU builds, the host compiler should get these compile flags as well.
diff: @@ -538,6 +538,7 @@ def set_cc_opt_flags(environ_cp):
  question, default_cc_opt_flags)
  for opt in cc_opt_flags.split():
  write_to_bazelrc('build:opt --copt=%s' % opt)
  + write_to_bazelrc('build:opt --host_copt=%s' % opt)
  write_to_bazelrc('build:opt --define with_default_optimizations=true')
  