Make sure that the sftp client tool uses the ssh client binary that we have
used to generate the configuration files, otherwise sftp might be using one
located in the preferred path compiled into sftp.

make use of mv's backup feature so that calling the ca-bundle target more than once will never fail; ignore error which can occure if for whatever reason there's no orignial ca-bundle.crt to rename.

Removed a few unnecessary requires SSL statements.

  (http://curl.haxx.se/bug/view.cgi?id=1889856): When using the gnutls ssl
  layer, cleaning-up and reinitializing curl ends up with https requests
  failing with "ASN1 parser: Element was not found" errors. Obviously a
  regression added in 7.16.3.

all curl's tests generated configuration and key files are fine, a real
connection is established to the test harness sftp server authenticating
and running a simple sftp remote pwd command.

The verification is done using OpenSSH's or SunSSH's sftp client tool with
a configuration file with the same options as the test harness socks server
with the exception that dynamic forwarding is not used for sftp.

instead of downloading it from the curl site

creates a suitable ca-bundle.crt file in PEM format for use with curl. The
recommended way to run it is to use 'make ca-bundle' in the build tree root.

it works the same way for configure-based platforms as for non-configure ones

for now this does rename the existing ca-bundle.crt to ca-bundle.crt.old;
maybe we can remove this once we are 100% sure that the new script works properly, and just overwrite the shipping one?

added a switch to display certdata.txt version header.

--vernum

  them all use the same (hopefully correct) logic to make it less error-prone
  and easier to introduce library-wide where it should be used.

ca-bundle.crt file as outdated and in need for replacement by anyone who wants
to verify modern peers as the one we have is from year 2000!

Improve handling of boundary conditions for huge requests.

Disable "swsbounce" mode when the received request
isn't for the same test and part number.

the whole 150000+ bytes struct, and also removing an equally big
additional buffer for pipelining treatment.

  use of the "is_in_pipeline" struct field.

HTTPS sites with OpenSSL-enabled libcurl (and pthreads) and thus do the
thread-locking and things openssl-style.

install process.  Note that mkinstalldirs appears to be used only
in some configurations.

which are deprecated in recent OpenSSH versions but are current for SunSSH.