ref: 40dc39bf7d8d17a84d6a2a427ca7facd8b2cb66b dir: /sys/src/libc/68000/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4