[Rd] Patch: port getbyhostname to getaddrinfo

[Jeroen Ooms]

Perhaps now that nanohttp has been removed, it is a good time to do
some related cleanups.

In both Linux and Windows, gethostbyname and gethostbyaddr are marked
as obsolete. POSIX.1-2008 removes the specifications of
gethostbyname(), gethostbyaddr(), and h_errno, recommending the use of
getaddrinfo(3) and getnameinfo(3) instead.

Webview: https://github.com/r-devel/r-svn/pull/42/files
Patch: https://github.com/r-devel/r-svn/pull/42.diff