Assigning the const value zero to a pointer to function
results in a null pointer value assignment to the function
pointer.

Assignment of any nonzero value is what should result in a
implementation compiler dependent result.

Since what we want to do here is the first case, this should
not trigger compiler warnings related with conversions from
'pointer to data' to 'pointer to function'.

Our autobuild test suite will judge.

and send(). Added needed HAVE_x defines.

to avoid picky compiler warnings, since this is what we want!

buffer used to store headers in the SessionHandle failed.

case when 401 or 407 are returned, *IF* no auth credentials have been given.
The CURLOPT_FAILONERROR option is not possible to make fool-proof for 401
and 407 cases when auth credentials is given, but we've now covered this
somewhat more.

You might get some amounts of headers transferred before this situation is
detected, like for when a "100-continue" is received as a response to a
POST/PUT and a 401 or 407 is received immediately afterwards.

Added test 281 to verify this change.

applies for asynch name resolves in general and not only ares

re-use connections (for pipelining) before the name resolving is done.

as well

reading the (local) CA cert file to let users easier pinpoint the actual
problem. CURLE_SSL_CACERT_BADFILE (77) is the new libcurl error code.

(when the resoling isn't completede yet) and not confuse it with a simple
connection re-use (non-pipelined).

to verify winsock API availability.

using winsock or winsock2 API.

resolving is completed so we must make sure to survive it and mark the
connection as async (ie not yet connected completely).

ever actually are used

could very well cause a negate number get passed in and thus cause reading
outside of the array usually used for this purpose.

We avoid this by using the uppercase macro versions introduced just now that
does some extra crazy typecasts to avoid byte codes > 127 to cause negative
int values.

#1579171

even when using curl_multi_socket() or even using the multi_perform() when
relying on multi_timeout() to be good.

c-ares name resolves, but now we do!