ref: 3c748ebc11c8a7e8513efcdd61a38a56c8ccfb5a dir: /sys/src/libc/sparc/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4