dev_stdclone
if (dev_stdclone(name, &subp, devnames[i], &unit) == 2)
else if (dev_stdclone(name, NULL, DEVICE_NAME, &unit) != 1)
if (dev_stdclone(dname, NULL, drv->cdevsw.d_name, &unit) == 1) {
int dev_stdclone(char *_name, char **_namep, const char *_stem, int *_unit);