ref: 33bdd7e6c2bbfc7e2373b4e8d0371fd89dc31e52 dir: /sys/src/libc/amd64/argv0.s/
GLOBL argv0(SB), $8 GLOBL _tos(SB), $8 GLOBL _privates(SB), $8 GLOBL _nprivates(SB), $4