ref: cf9a3c2ad5a1e1a371cad0b6d5fc4164a68caf76 dir: /sys/src/libc/arm/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4