ref: 8b6ec7da32b39b2f1af45b6f6dff4cc9e836d5ac dir: /sys/src/libc/amd64/argv0.s/
GLOBL argv0(SB), $8 GLOBL _tos(SB), $8 GLOBL _privates(SB), $8 GLOBL _nprivates(SB), $4