+void xheader_xattr_init (struct tar_stat_info *st);
+void xheader_xattr_free (struct xattr_array *vals, size_t sz);
+void xheader_xattr_copy (const struct tar_stat_info *st,
+ struct xattr_array **vals, size_t *sz);
+void xheader_xattr_add (struct tar_stat_info *st,
+ const char *key, const char *val, size_t len);