ref: 3568e27ec8774a212564c8d2bf6b3d9a19d4d571 dir: /sys/src/libc/386/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4