Value stored to 'len' is never read

Use (void)[variable] to inhibit unused argument/variables warnings.

Use Curl_ssl_connect_nonblocking() when upgrading the connection to
TLS/SSL while using the multi interface.

When NSS-powered libcurl connected to a SSL server with
CURLOPT_SSL_VERIFYPEER equal to zero, NSS remembered that the peer
certificate was accepted by libcurl and did not ask the second time when
connecting to the same server with CURLOPT_SSL_VERIFYPEER equal to one.

This patch turns off the SSL session cache for the particular SSL socket
if peer verification is disabled.  In order to avoid any performance
impact, the peer verification is completely skipped in that case, which
makes it even faster than before.

Bug: https://bugzilla.redhat.com/678580

As a follow-up to commit 8831000b: don't assume that the SSL powered
protocol alternatives are available.

Use the new flags field and stop using the old protocol defines.

Removed a fixed issue, added five new existing ones and clarified one of
the previous ones.

The PROT_* set of internal defines for the protocols is no longer
used. We now use the same bits internally as we have defined in the
public header using the CURLPROTO_ prefix. This is for simplicity and
because the PROT_* prefix was already used duplicated internally for a
set of KRB4 values.

The PROTOPT_* defines were moved up to just below the struct definition
within which they are used.

The protocol handler struct got a 'flags' field for special information
and characteristics of the given protocol.

This now enables us to move away central protocol information such as
CLOSEACTION and DUALCHANNEL from single defines in a central place, out
to each protocol's definition. It also made us stop abusing the protocol
field for other info than the protocol, and we could start cleaning up
other protocol-specific things by adding flags bits to set in the
handler struct.

The "protocol" field connectdata struct was removed as well and the code
now refers directly to the conn->handler->protocol field instead. To
make things work properly, the code now always store a conn->given
pointer that points out the original handler struct so that the code can
learn details from the original protocol even if conn->handler is
modified along the way - for example when switching to go over a HTTP
proxy.

- Keep RPG binding, STRING_* table end check and OS400 README up to date.

Lines that are indented with at least 5 spaces get special treatment by
the script that converts it to HTML on the site.

The non-blocking connect improvement for IMAP showed that we didn't
properly define the Curl_ssl_connect_nonblocking function for non-SSL
builds.

Reported by: Tor Arntsen

Several --with-XXX options claimed the wrong default path in their help
outputs.

Reported by: Vincent Torri

Only download and convert the certdata to the ca-bundle.crt if Mozilla
changed the data

The Perl LWP module (which in a bit of a circular reference is used by
mk-ca-bundle.pl) is now indirectly using this script. I made this small
tweak to make it easier to automatically maintain the generated
ca-bundle.crt file in version control.

Some protocols have to call the underlying functions without regard to
what exact state the socket signals. For example even if the socket says
"readable", the send function might need to be called while uploading,
or vice versa. This is the case for libssh2 based protocols: SCP and
SFTP and we now introduce a define to set those protocols and we make
the multi interface code aware of this concept.

This is another fix to make test 582 run properly.

As a new state recently was added to the IMAP state machine it has to be
in the array of names as well as otherwise libcurl crashes when a debug
version runs...

Commit ca37692b should now hopefully make it run

For uploads we want to use the _sending_ function even when the socket
turns out readable as the underlying libssh2 sftp send function will
deal with both accordingly. This is what the cselect_bits magic is for.

Fixes test 582.

This reverts commit b8478187.

These issues are now addressed:

276 - Karl M's vc makefile patch
277 - The "Stall when uploading to sftp using multi interface"  bug
279 - curl_multi_remove_handle() crashes
280 - Marcus Sundberg's gss patch

http_negotiate_sspi.c was added to the source tree recently

Make GSS authentication work when a curl handle is reused for multiple
authenticated requests, by always setting negdata->state in
output_auth_headers().

Signed-off-by: Marcus Sundberg <marcus.sundberg@aptilo.com>

This test case is meant to verify that the logic in commit
60172a04 actually works. This test failed for me before that
change and it works after it.

When using the multi interface and a handle using SFTP was removed very
early on, we would get a segfault due to the code assumed data was there
that hadn't yet been setup.

Bug: http://curl.haxx.se/mail/lib-2011-03/0066.html
Reported by: Saqib Ali

recvfrom in bionic (the android libc) deviates from POSIX and uses a
const in the 5th argument ("const struct sockaddr *") so the check now
tests for that as well.

Both SFTP and SCP are protocols that need to shut down stuff properly
when the connection is about to get torned down. The primary effect of
not doing this shows up as memory leaks (when using SCP or SFTP with the
multi interface).

This is one of the problems detected by test 582.

As we know how much to send, we can and should stop once we've sent that
much data as it avoids having to rely on other mechanisms to detect the
end.

This is one of the problems detected by test 582.

Reported by: Henry Ludemann <misc@hl.id.au>

When using the multi_socket API to do SFTP upload, it is important that
we set a quick expire when leaving the SSH_SFTP_UPLOAD_INIT state as
there's nothing happening on the socket so there's no read or write to
wait for, but the next libssh2 API function needs to be called to get
the ball rolling.

This is one of the problems detected by test 582.

Reported by: Henry Ludemann <misc@hl.id.au>

All C and H files now (should) feature the proper project curl source
code header, which includes basic info, a copyright statement and some
basic disclaimers.