ref: 74bcc2aa4c0b8e2d9915ae2cda6e4b2fabf56e95 dir: /sys/src/libc/mips/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4