setmachine
static void setmachine(const char *, const char *, struct nvlist *, int);
XMACHINE WORD '\n' { setmachine($2,NULL,NULL,0); }
| XMACHINE WORD WORD '\n' { setmachine($2,$3,NULL,0); }
| XMACHINE WORD WORD subarches '\n' { setmachine($2,$3,$4,0); }
| IOCONF WORD '\n' { setmachine($2,NULL,NULL,1); }