c-ares name resolves, but now we do!

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>.

Curl_freeaddrinfo() and Curl_ip2addr().

(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).

code rearrange to fit the future better.

The tag 'before_ftp_statemachine' was set just before this commit in case
of future need.

CURLE_OK or CURLE_OUT_OF_MEMORY.
Add typecast in hostares.c.

operation to the caller. Disconnecting has the disadvantage that the conn
pointer gets completely invalidated and this is not handled on lots of places
in the code.

linked list for name resolved data, even on hosts/systems with only IPv4
stacks as this simplifies a lot of code.

memory.h is included everywhere for this.

internally-used name.

when ares fails to resolve a name. This was fixed before but somehow has
fallen out again!

all things up to work with encoded host names internally, as well as keeping
'display names' to show in debug messages. IDN resolves work for me now using
ipv6, ipv4 and ares resolving. Even cookies on IDN sites seem to do right.

usage.