memdebug log file after every line and avoid losing the last few log
entries if curl crashes.

This was possible on debug c-ares enabled builds when both CURL_MEMDEBUG
and CARES_MEMDEBUG environment variables were set. Leading to a file handle
leak even when both variables had the same value, and wierd test suite
results when different.

(and besides, we should be using the same %-code for all pointers)

Set errno = ENOMEM on faild countcheck().

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.

use %zd when outputting size_t

fopen() as well.

one to prevent that.

argument to also not force the casual includer to know about the socklen_t
type.

sockaddr *. This has the added benefit that source files that include
memdebug.h doesn't have to know about "sockaddr".

to memdebug the ares stuff as well.

warnings. Minor edits by me.

allocation calls will succeed, the following will return NULL!

way for emacs, and vim users should provide a similar non-polluting style

can destroy the full allocated area just before we free it

makes it easier to disable debug output when built with debug functions