Reported by Tatsuhiro Tsujikawa

http://curl.haxx.se/mail/lib-2012-06/0371.html

Allow NTLM authentication when building using SecureTransport (Darwin) for SSL.

This uses CommonCrypto, a cryptography library that ships with all versions of
iOS and Mac OS X. It's like OpenSSL's libcrypto, except that it's missing a few
less-common cyphers and doesn't have a big number data structure.

Before commit 2dded8fe (dec 2010) there was logic that used
RAND_screen() at times and now I remove the leftover #ifdef check for
it.

The seeding code that uses Curl_FormBoundary() in ossl_seed() is dubious
to keep since it hardly increases randomness but I fear I'll break
something if I remove it now...

- Renamed st_ function prefix to darwinssl_
- Renamed Curl_st_ function prefix to Curl_darwinssl_
- Moved the duplicated ssl_connect_done out of the #ifdef in lib/urldata.h
- Fixed a teensy little bug that made non-blocking connection attempts block
- Made it so that it builds cleanly against the iOS 5.1 SDK

Fixed warning: dereferencing pointer does break strict-aliasing rules
by using a union inside the struct Curl_sockaddr_storage declaration.

curl_ntlm_msgs.c would previously use an #ifdef maze and direct
SSL-library calls instead of using the SSL layer we have for this
purpose.

Bug: http://curl.haxx.se/mail/lib-2012-06/0094.html
Reported by: Dan

Removed two, not intended to exist, RESOURCE declarations.

Bug: http://curl.haxx.se/bug/view.cgi?id=3535977

And sorted configuration hunks to reflect same internal order
as the one shown in the usage message.

Increase decrypted and encrypted cache buffers using limitted
doubling strategy. More information on the mailinglist:
http://curl.haxx.se/mail/lib-2012-06/0255.html

It updates the two remaining reallocations that have already been there
and fixes the other one to use the same "do we need to increase the
buffer"-condition as the other two.  CURL_SCHANNEL_BUFFER_STEP_SIZE was
renamed to CURL_SCHANNEL_BUFFER_FREE_SIZE since that is actually what it
is now.  Since we don't know how much more data we are going to read
during the handshake, CURL_SCHANNEL_BUFFER_FREE_SIZE is used as the
minimum free space required in the buffer for the next operation.
CURL_SCHANNEL_BUFFER_STEP_SIZE was used for that before, too, but since
we don't have a step size now, the define was renamed.

In schannel_connect_step2() doread should be initialized based
on connssl->connecting_state.

Process extra data buffer before returning from schannel_connect_step2.
Without this change I've seen WinCE hang when schannel_connect_step2
returns and calls Curl_socket_ready.

If the encrypted handshake does not fit in the intial buffer (seen with
large certificate chain), increasing the encrypted data buffer is necessary.

Fixed warning in curl_schannel.c line 1215.

process.h is not present on WinCE

Implemented timeout loop in schannel_send while sending data.  This
is as close as I think we can get to write buffering; I put a big
comment in to explain my thinking.

With some committer adjustments

Replaced calls to swrite with Curl_write_plain and calls to sread
with Curl_read_plain.

With some committer adjustments

Make the Schannel implementation use libcurl's default buffer size
for the initial received encrypted and decrypted data cache buffers.
The implementation still needs to handle more data since more data
might have already been received or decrypted during the handshake
or a read operation which needs to be cached for the next read.

curl_schannel.c - implemented graceful SSL shutdown.  If we fail to
shutdown the connection gracefully, I've seen schannel try to use a
session ID for future connects and the server aborts the connection
during the handshake.

curl_schannel.c - auto certificate validation doesn't seem to work
right on CE.  I added a method to perform the certificate validation
which uses CertGetCertificateChain and manually handles the result.

Added helper methods InitSecBuffer() and InitSecBufferDesc() to make it
easier to set up SecBuffer & SecBufferDesc structs.

Avoid usage of some MS type synonyms to allow compilation with
compiler headers that don't define these, using simpler synonyms.

Coverity actually pointed out flawed logic in the previous call to
Curl_strntoupper() where the code used sizeof() of a pointer to pass in
a size argument. That code still worked since it only needed to
uppercase 4 letters. Still, the entire malloc/uppercase/free sequence
was pointless since the code has already matched the string once in the
condition that starts the block of code.

As spotted by Coverity, va_end() was not used previously. To make it
used I took away a bunch of return statements and made them into
assignments instead.