ref: 88181e1c5c8d19e61c76b93620abcbc7c2e57481 dir: /sys/src/libc/386/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4