ref: 4adb1d68d1a958c2ee3c5cfe2e26968e13dcfc1b dir: /sys/src/libc/amd64/argv0.s/
GLOBL argv0(SB), $8 GLOBL _tos(SB), $8 GLOBL _privates(SB), $8 GLOBL _nprivates(SB), $4