ref: fcc5e75d07e5bc6cb3ddac6d9a437e7ec62d0d95 dir: /sys/src/libc/alpha/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4