message: Allow environment variables to execution of flatc command
diff: @@ -320,6 +320,7 @@ def _gen_flatbuffer_srcs_impl(ctx):
  src.path,
  ],
  progress_message = "Generating flatbuffer files for {}:".format(src),
  + use_default_shell_env = True,
  )
  return [
  DefaultInfo(files = depset(outputs)),
  