ref: 1d2767a6794afc7dfa1d6fb0f6dfa9e93f5c932d dir: /sys/src/libc/mips/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4