ref: 2e1cd4eea3163cc033d0eca6ba5e5fd4efc4a5f2 dir: /sys/src/libc/amd64/argv0.s/
GLOBL argv0(SB), $8 GLOBL _tos(SB), $8 GLOBL _privates(SB), $8 GLOBL _nprivates(SB), $4