ref: f3b5bcffceb05ce2b9f8c19d2e0721f3e54098e8 dir: /sys/src/libc/arm/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4