ref: 76b51dc816a4e6ad1d21b6b40b8ea32a57bd47a6 dir: /sys/src/libc/arm/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4