ref: 03c144570ffbe9e8be52ba5b2dd9e3dbe7f0bae1 dir: /sys/src/libc/mips/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4