ref: 63fba6deee07e5b5c3260b67b5c9d40b49b138c7 dir: /sys/src/libc/sparc/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4