This adds to the work done for issue #15990 (i.e. f44b8d69e5fc and the
commits referenced there).

Fix line buffering of socket._fileobject

#16666: document default values for socket.getaddrinfo in the text to clarify that it doesn't accept keyword args.

Patch Serhiy Storchaka.

Patch by Anton Kasyanov.

Fix Issue15701 - HTTPError info method call raises AttributeError. Fix that to return headers correctly

Patch by Chris Jerdonek.

Patch by Serhiy Storchaka.

Patch by Serhiy Storchaka.

Fix issue #16646: ftplib.FTP.makeport() might lose socket error details.  (patch by Serhiy Storchaka)

Patch by Ashish Nitin Patil.

Issue #16626: Fix infinite recursion in glob.glob() on Windows when the pattern contains a wildcard in the drive or UNC path.
Patch by Serhiy Storchaka.

Patch by Sebastian Kreft.

Issue #16298: In HTTPResponse.read(), close the socket when there is no Content-Length and the incoming stream is finished.
Patch by Eran Rundstein.

Found by Clang trunk's Undefined-Behavior Sanitizer.  [more to come]