ref: 08a9a6952dfa9ace5b4ae6fa1614c97d4a945ece dir: /sys/src/libc/68020/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4