ref: 74343d66b2ba1043577dbb6a02f97d5e06b3a7c5
parent: 6949cc1d5185d10de1c78e5a10526b2949f3e35a
author: phil9 <telephil9@gmail.com>
date: Thu Sep 2 15:24:48 EDT 2021
Add missing _SLEEP declaration. We use plan9 sleep (through its syscall name _SLEEP) in the plumber thread to have a millisecond precision instead of the POSIX sleep and its second precision.