Found with codespell.

Move ipv6-functional-probe into a single function that is used from all
places that need to know.

Make the probe function store the result in a static variable so that
subsequent invokes just returns the previous result and won't have to
probe again.

The IP version choice was previously only in the UserDefined struct
within the SessionHandle, but since we sometimes alter that option
during a request we need to have it on a per-connection basis.

I also moved more "init conn" code into the allocate_conn() function
which is designed for that purpose more or less.

No resolver anymore needs to use AI_CANONNAME and do reverse
lookups.  We should work hard to avoid having code that relies on
it.

removal of Curl_addrinfo_copy(), Curl_addrinfo6_callback(), and
Curl_addrinfo4_callback()

of messages atomic, on systems where an fwrite of a memory buffer is atomic.

setup_once.h.  Inclusion of each header file is based on the definition of
NEED_MALLOC_H and NEED_MEMORY_H respectively.

implementation from lib/hostip6.c to lib/curl_addrinfo.c
and prototypes from lib/hostip.h to lib/curl_addrinfo.h

Use a wrapper function to call system's getaddrinfo().

address in an IPv6 capable libcurl.

while () => while()
and some other minor re-indentings

libcurl. This also makes the options change name to --krb (from --krb4) and
CURLOPT_KRBLEVEL (from CURLOPT_KRB4LEVEL) but the old names are still

since they're already included through "setup.h".

behaviour and a socket leak

Simplify check for NEED_MALLOC_H, and make more explicit that NEED_MALLOC_H shall be defined if <malloc.h> header file must be included even when including <stdlib.h>.

(http://curl.haxx.se/bug/view.cgi?id=1481217), with follow-ups by Michele Bini
and David Byron. libcurl previously wrongly used GetLastError() on windows to
get error details after socket-related function calls, when it really should
use WSAGetLastError() instead.

When changing to this, the former function Curl_ourerrno() is now instead
called Curl_sockerrno() as it is necessary to only use it to get errno from
socket-related functions as otherwise it won't work as intended on Windows.

(more logical).

Fix compiler warning and compatibility issue with the type of the parameter used in getnameinfo() to receive the length of the sockaddr struct.

we really have no use for reverse lookups of the address.

I truly hope these are the last reverse lookups we had lingering in the
code!