ref: 4410517b44fd2610abe0dcd1349bb3e6b3c5ddb8 dir: /sys/src/libc/alpha/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4