ref: 3e94fbcf9c6caa7cde6051bec82cae3b1c8d3e11 dir: /sys/src/libc/mips/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4