rem: if (xstrtod (arg, NULL, &ret_val))
add: if (! xstrtod (arg, NULL, &ret_val, c_strtod))
context: scan_double_arg (const char *arg){  double ret_val;  if (xstrtod (arg, NULL, &ret_val))    {      error (0, 0, _("invalid floating point argument: %s"), arg);      usage (EXIT_FAILURE);    }  return ret_val;}