ref: a8fdcbf3a2e100f1e8f2ee30bead4d0ed0172b41 dir: /sys/src/libc/mips/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4