ref: 5c6357de8bda7c5fe0a7fa4ab31b365a9ae8e6fb dir: /sys/src/libc/amd64/argv0.s/
GLOBL argv0(SB), $8 GLOBL _tos(SB), $8 GLOBL _privates(SB), $8 GLOBL _nprivates(SB), $4