sub die_bug {
    my $bugid = shift;
    print STDERR
	("$Global::progname: This should not happen. You have found a bug.\n",
	 "Please contact <parallel\@gnu.org> and follow\n",
	 "https://www.gnu.org/software/parallel/man.html#REPORTING-BUGS\n",
	 "\n",
	 "Include this in the report:\n",
	 "* The version number: $Global::version\n",
	 "* The bugid: $bugid\n",
	 "* The command line being run\n",
	 "* The files being read (put the files on a webserver if they are big)\n",
	 "\n",
	 "If you get the error on smaller/fewer files, please include those instead.\n");
    ::wait_and_exit(255);
}