fix #147: Stack Exhaustion Problem caused by some parsing functions in regcomp.c making recursive calls to themselves.
callout_tag_entry_raw(CalloutTagTable* t, UChar* name, UChar* name_end,
                      CalloutTagVal entry_val)
{
  int r;
  CalloutTagVal val;

  if (name_end - name <= 0)
    return ONIGERR_INVALID_CALLOUT_TAG_NAME;

  val = callout_tag_find(t, name, name_end);
  if (val >= 0)
    return ONIGERR_MULTIPLEX_DEFINED_NAME;

  r = onig_st_insert_strend(t, name, name_end, (HashDataType )entry_val);
  if (r < 0) return r;

  return ONIG_NORMAL;
}

callout_tag_entry_raw(CalloutTagTable* t, UChar* name, UChar* name_end,
                      CalloutTagVal entry_val)
{
  int r;
  CalloutTagVal val;

  if (name_end - name <= 0)
    return ONIGERR_INVALID_CALLOUT_TAG_NAME;

  val = callout_tag_find(t, name, name_end);
  if (val >= 0)
    return ONIGERR_MULTIPLEX_DEFINED_NAME;

  r = onig_st_insert_strend(t, name, name_end, (HashDataType )entry_val);
  if (r < 0) return r;

  return ONIG_NORMAL;
}
