support for the OS/400 Secure Sockets Layer library

some few internal identifiers to avoid conflicts, which could be useful on
other platforms.

to occur in a couple of tests.

verifies the bug fix in #1757328.

from the test server code as they served no real purpose. The test server is
here to serve for the test cases, not to attempt to function as a real server!

lower case for consistency since sftp commands are case insensitive.

(http://curl.haxx.se/bug/view.cgi?id=1757328) and submitted a patch. It turns
out we broke login to FTP servers that don't require (nor understand) PASS
after the USER command

keys that small.

issue is in libssh2 and not freeing a dynamic error message during cleanup.

really reduce security since in the common case of a daily automated build
the keys are only used for a single test run lasting a few minutes before
being deleted.

a new directory listing format that newer libssh2's can provide.  This
is probably NOT sufficient to handle all directory listing formats that
server's can provide and should be revisited.

a control connection that was deemed "dead" to yet be re-used in a following
request. We must make sure the connection gets closed on this situation.

  getaddrinfo() sorts the response list which effectively kills how libcurl
  deals with round-robin DNS entries. All details:
    http://curl.haxx.se/mail/lib-2007-07/0168.html
  initial suggested function to use for randomizing the response:
    http://curl.haxx.se/mail/lib-2007-07/0178.html

can take advantage of it however they see fit!

added hint to compile with SSPI with MSVC6 without PSDK.

Regev on the libcurl mailing list on 10 Jul 2007, converted to a test case.

really hard if the test server can't be resolved (like for ::1 ipv6)