ref: 1cfe7fded39233cf93f110b0c63b9c5c9f2e7f3e dir: /sys/src/libc/386/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4