ref: 85d0f0e1a2c05afee5a101c1e51a3ddd2ff2a5f6 dir: /sys/src/libc/68020/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4