ref: d5cf062e7a0e3a6b2c2939c7615ffd722cdbf1a8 dir: /sys/src/libc/arm/argv0.s/
GLOBL argv0(SB), $4 GLOBL _tos(SB), $4 GLOBL _privates(SB), $4 GLOBL _nprivates(SB), $4