ref: e684b2a3fbd7d077ba4dabbd7fb4c7d1ff09c30c dir: /sys/src/libc/sparc/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4