ref: 95db2e9ddeaa3e85d4c7867541da72476db4a3c8 dir: /sys/src/libc/riscv64/argv0.s/
GLOBL argv0(SB), $XLEN GLOBL _tos(SB), $XLEN GLOBL _privates(SB), $XLEN GLOBL _nprivates(SB), $XLEN