ref: e0745d0e8dcbb020e6b5debb46d8dcc24a1d6fc7 dir: /sys/src/libc/arm/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4