client certificates! (http://curl.haxx.se/bug/view.cgi?id=1348930).

in files that actually need the struct.

step counter by adding :[num] within the brackets when specifying a range.

  range increasing the number with 10 for every step. Requested by Jose:
  http://curl.haxx.se/feedback/display.cgi?id=11315662266802

since IPv6 support is required.

Added -D'efines'.

<ws2tcpip.h> since IPv6 is no longer optional (was it ever?)

Replace <winsock.h> with <winsock2.h> + <ws2tcpip.h>
(ala libcurl since IPv6 is not optional now).

we really have no use for reverse lookups of the address.

I truly hope these are the last reverse lookups we had lingering in the
code!

version of libcurl with different Windows versions. Current version of
libcurl imports SSPI functions from secur32.dll. However, under Windows NT
4.0 these functions are located in security.dll, under Windows 9x - in
secur32.dll and Windows 2000 and XP contains both these DLLs (security.dll
just forwards calls to secur32.dll).

Dmitry's patch loads proper library dynamically depending on Windows
version. Function InitSecurityInterface() is used to obtain pointers to all
of SSPI function in one structure.
: ----------------------------------------------------------------------

  Curl_ossl_connect(), the Curl_gtls_connect() function does not send the user
  certificate to the peer. In fact, it ignores the conn->data->set.cert field
  completely, it always uses the anonymous credentials. See
  http://curl.haxx.se/bug/view.cgi?id=1348930

 1.9 Where do I buy commercial support for curl?
 1.10 How many are using curl?
 6.7 What are my obligations when using libcurl in my commerical apps?

Edited a few other paragraphs slightly.