static char *xstrdup_tolower(const char *str)
{
	char *p, *dup = xstrdup(str);
	for (p = dup; *p; p++)
		*p = tolower(*p);
	return dup;
}
static char *xstrdup_tolower(const char *str)
{
	char *p, *dup = xstrdup(str);
	for (p = dup; *p; p++)
		*p = tolower(*p);
	return dup;
}