ref: 2c47b855b1ea9f9c0fd66f14bda93ff6a33a5df9 dir: /sys/src/libc/68000/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4