check_chunk (void *data) {
  if (chunk_clean) {
    fprintf (stderr, "%s: test failed: "
             "chunk callback invoked multiple times\n", progname);
    exit (EXIT_FAILURE);
  }
  chunk_clean = true;
}
check_chunk (void *data) {
  if (chunk_clean) {
    fprintf (stderr, "%s: test failed: "
             "chunk callback invoked multiple times\n", progname);
    exit (EXIT_FAILURE);
  }
  chunk_clean = true;
}