ref: 9cf3dc9a259cadc80e6d3840c658ef1d5f7c94a4 dir: /sys/src/libc/68020/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4