I saw the thread fix-up recently. Based on the comments, it seems setcontext/getcontext versus pthreads is becoming less of an issue these days.
Re:A Week with Plan 9
by butterisgood on Thursday January 14, 2021 @01:43PM
(#25780335)
Well one is supposed to implement cooperatively scheduled coroutines, and the other is pthreads.
It pre-dates Go by a bit for sure, and Go was already underway at Google with Rob Pike before Russ came over (per my recollection).
That said, I too use plan9port, on my mac, for Acme mainly.
Russ just fixed up the thread library so it works more uniformly (and correctly) on all platforms - including Apple Silicon.