ref: b2e29cf3158d6e8c6a0263cb1bbb06e72a21f7fb dir: /sys/src/libc/68000/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4