ref: 2263bb8f2b654c1d824a0fcb53bb4ffb92de2d2f dir: /sys/src/libc/alpha/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4