ref: 922fc6faa00ab4e0f46b9f3d3c6bbd25a1c2201d dir: /sys/src/libc/68000/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4