Replace non-standard pthread_yield with sched_yield
Replace non-standard pthread_yield with sched_yield

pthread_yield is not compatible with environments like Alpine Linux. Furthermore, this function seems to be implemented as a call to sched_yield on most Linux systems. The man page recommends the use of sched_yield instead.

GammaUNC/FasTC,GammaUNC/FasTC,GammaUNC/FasTC,GammaUNC/FasTC