ref: 2c5dfc8dbd6cf36adedf1b4be35e49f8a8d5f3cf dir: /sys/src/libc/386/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4