ref: d5f2d2cc3fc7c2d3701e906df5d2d53781c4ee9c dir: /sys/src/libc/amd64/argv0.s/
GLOBL argv0(SB), $8 GLOBL _tos(SB), $8 GLOBL _privates(SB), $8 GLOBL _nprivates(SB), $4