ref: 4fedd7d4fe1c3b509c84d12e971aaa466b8b4b3d dir: /sys/src/libc/68000/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4