ref: 2a3e8eba4a6eda280d52ddb256c13a0eb33b0f45 dir: /sys/src/libc/arm/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4