ref: a7f1bb9a9e1720b22d1fbed16e7527fa2cd0d82c dir: /sys/src/libc/arm/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4