ref: 3bb0b9f4ea46431189b2cae2a6c2887f786d822a dir: /sys/src/libc/68000/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4