close is closesocket. Also some of the headers are different
and inet_aton should be inet_pton.

Change-Id: I9eee0880d91833bdd3bcf0f2a352923c9fb1a891
Reviewed-on: https://boringssl-review.googlesource.com/1864
Reviewed-by: Adam Langley <agl@google.com>

Initial fork from f2d678e6e8 (1.0.2 beta).

(This change contains substantial changes from the original and
effectively starts a new history.)