atomic_store wasn't working on windows
- fixed a typo in the win32 version of the atomic_store macro
- moved the unix version to lib/isc/unix/include/isc so it's more obvious in the future that it isn't the only copy
- add atomic_bool implementation in win32 version of stdatomic.h
- fixed copy&paste error in win32 atomic_fetch_add macro
Edited by Ondřej Surý