ref: 3bc4e5a6d568889eeeb2d0b7d443c0a3e02fb499 dir: /sys/src/libc/arm/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4