ref: 3fbd9f07c8ce1a8fe1910d2edf71cda3dcf5703e dir: /sys/src/libc/alpha/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4