Add posix threads support for macOS #1618
Description
Can we add a possibility to use POSIX threads for the macOS? It seems to be not straightforward to do myself - all the code is mixed across many files. Thanks!
P.S. Maybe it is even better if we share all the POSIX-code among several targets which support it. Right now, for example, the pthread_setschedprio function is defined in the /linux-like/linux but it shouldn't be Linux-only available.