ref: 4e015eb5c7ba7ae1cb7b2e26997a7ba0eb02b626 dir: /sys/src/libc/alpha/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4