ash: reduce global data/bss usage

(add/remove: 4/29 grow/shrink: 76/21 up/down: 1007/-1713)    Total: -706 bytes
   text    data     bss     dec     hex filename
 777206    1084    8976  787266   c0342 busybox_old
 778077     908    7568  786553   c0079 busybox_unstripped

1 file changed