message: Use archive_format for determining if gnu style archives should be emitted
  Fixes
diff: @@ -41,7 +41,7 @@ fn new(sess: &'a Session, output: &Path, input: Option<&Path>) -> Self {
  lib_search_paths: archive_search_paths(sess),
  use_native_ar: false,
  // FIXME test for linux and System V derivatives instead
  - use_gnu_style_archive: !sess.target.target.options.is_like_osx,
  + use_gnu_style_archive: sess.target.target.options.archive_format == "gnu",
  };
  let (src_archives, entries) = if let Some(input) = input {
  