ref: 32a27378239aadb80d6d17f2cfbc9b5ba9a9b2c0 dir: /sys/src/libc/386/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4