On some ancient distributions such as RHEL-3, <gssapi/gssapi_krb5.h> needs
to be processed after <gssapi/gssapi.h>, but does not include it itself.
This patch checks for <gssapi/gssapi.h> first and then includes it
in the test for <gssapi/gssapi_krb5.h>, resolving the problem.

Without the patch, <gssapi/gssapi_krb5.h> is "present but cannot be
compiled".

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

This code would previously use dns_entry->addr->ai_canonname
instead of the given host name, which caused us grief and
problems since not all our resolver options do the reverse lookup
and I would also guess that it caused problems with KRB5/GSS with
virtual name-based hosts. Now the host name from the URL is used.

Based on a patch from the FreeBSD ports by Peter Pentchev.

As reported in bug report #2987196, the code for ipv6 already did
the setting of this bit correctly so we copied that logic into
the Curl_ipv4_resolve_r() function as well. KRB code is the only
code we know that might need the cannonical name so only resolve
it for such requests!

Signed-off-by: Tor Arntsen <tor@spacetec.no>

no need to create a var - lets just return the status var itself.

The section that describes how to work with timeouts was
misleading and could easily trick users to use the wrong API.

c-ares has had its own URL for a while and we should point
people to that. It also works with IPv6 since a long time.

curl_multi_timeout(3) is simply the wrong function to use
if you're using the multi_socket API and this document now
states this pretty clearly to help guiding users.

I've done this blindly, and the last piece that works with ares
should possibly be done differently now that c-ares isn't a
subtree within the curl tree anymore...

Prefixing the FTP quote commands with an asterisk really only
worked for the postquote actions. This is now fixed and test case
227 has been extended to verify.

Reported by Guenter Knauf.

Signed-off-by: Ben Greear <greearb@candelatech.com>

Matt Wixson found and fixed a bug in the SCP/SFTP area where the
code treated a 0 return code from libssh2 to be the same as
EAGAIN while in reality it isn't. The problem caused a hang in
SFTP transfers from a MessageWay server.