/* Set to rtsTrue if there are threads on the blackhole_queue, and
* it is possible that one or more of them may be available to run.
* This flag is set to rtsFalse after we've checked the queue, and
/* Set to rtsTrue if there are threads on the blackhole_queue, and
* it is possible that one or more of them may be available to run.
* This flag is set to rtsFalse after we've checked the queue, and