ref: 6ef7d2b79c9dbc015fb8c7caf95960bfb4a8ee53 dir: /sys/src/libc/arm64/argv0.s/
GLOBL argv0(SB), $8 GLOBL _tos(SB), $8 GLOBL _privates(SB), $8 GLOBL _nprivates(SB), $4