ref: 2cc152f9e1c7435ff0a5bcc7c4467249afe227e9 dir: /sys/src/libc/alpha/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4