ref: 2d06aac2abbd22757b6aa33b4fdc0c9ead4b7d50 dir: /sys/src/libc/mips/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4