[Bug libstdc++/80538] Probably unwanted thread yield for thread::sleep_for with < 1s

[zulliger at indel dot ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80538

--- Comment #2 from zulliger at indel dot ch ---
Thank's for clarifying! If sleep(0)'s behaviour is undefined regarding 'thread
yielding', then my whole point is wrong.

(It seems I didn't read stackoverflow & Co carefully enough, as the statement I
saw was specific to Microsofts Sleep(int MilliSeconds) which indeed yields).