Issue #22834: Have import suppress FileNotFoundError when the current
working directory no longer exists.

Thanks to Martin Panter for the bug report.
Issue #19720: Suppressed context for some exceptions in importlib.
Issue #17293: socket.gethostbyname() can raise an exception of FreeBSD.

--HG--
branch : 3.4
Issue #19720: Suppressed context for some exceptions in importlib.