POSIX.1-2001. Note that RFC 2553 defines a prototype where the last parameter cnt is of type size_t.
Many systems follow RFC 2553. Glibc 2.0 and 2.1 have size_t, but 2.2 has socklen_t.

  ares_cancel() is used, to be ARES_ECANCELLED instead of ARES_ETIMEOUT to
  better allow the callback to know what's happening.

yet another issue not yet sorted out

  fails to get inited by other means. This fixes a case of when the c-ares
  init fails when internet access is fone.

and the name length differ in those cases and thus leave the matching function
unmodified from before, as the matching functions never have to bother with
the zero bytes in legitimate cases. Peter Sylvester helped me realize that
this fix is slightly better as it leaves more code unmodified and makes the
detection a bit more obvious in the code.

Cantor. My previous attempt was half-baked and didn't cover the normal CN
case.

  should introduce an option to disable SNI, but as we're in feature freeze
  now I've addressed the obvious bug here (pointed out by Peter Sylvester): we
  shouldn't try to enable SNI when SSLv2 or SSLv3 is explicitly selected.
  Code for OpenSSL and GnuTLS was fixed. NSS doesn't seem to have a particular
  option for SNI, or are we simply not using it?

  (http://curl.haxx.se/bug/view.cgi?id=2829955) mentioning the recent SSL cert
  verification flaw found and exploited by Moxie Marlinspike. The presentation
  he did at Black Hat is available here:
  https://www.blackhat.com/html/bh-usa-09/bh-usa-09-archives.html#Marlinspike

  Apparently at least one CA allowed a subjectAltName or CN that contain a
  zero byte, and thus clients that assumed they would never have zero bytes
  were exploited to OK a certificate that didn't actually match the site. Like
  if the name in the cert was "example.com\0theatualsite.com", libcurl would
  happily verify that cert for example.com.

  libcurl now better use the length of the extracted name, not assuming it is
  zero terminated.

  only in some OpenSSL installs - like on Windows) isn't thread-safe and we
  agreed that moving it to the global_init() function is a decent way to deal
  with this situation.

  CURLOPT_NOPROXY to "*", or to a host that should not use a proxy, I actually
  could still end up using a proxy if a proxy environment variable was set.

  something beyond ascii but currently libcurl will only pass in the verbatim
  string the app provides. There are several browsers that already do this
  encoding. The key seems to be the updated draft to RFC2231:
  http://tools.ietf.org/html/draft-reschke-rfc2231-in-http-02

can't seem to catch up

243 - ftp QUOTE commands that are allowed to fail but not close the connection
is done

  CURLOPT_PREQUOTE) now accept a preceeding asterisk before the command to
  send when using FTP, as a sign that libcurl shall simply ignore the response
  from the server instead of treating it as an error. Not treating a 400+ FTP
  response code as an error means that failed commands will not abort the
  chain of commands, nor will they cause the connection to get disconnected.

"you replaced the old SSLeay_add_ssl_algorithms() call
with OpenSSL_add_all_algorithms(), however unlike the name suggests,
the second function is not a superset of the first. When using SSL
both these functions will need to be called in order to offer complete
functionality"

  out that OpenSSL-powered libcurl didn't support the SHA-2 digest algorithm,
  and provided the solution too: to use OpenSSL_add_all_algorithms() instead
  of the older SSLeay_* alternative. OpenSSL_add_all_algorithms was added in
  OpenSSL 0.9.5

independent of libssh2 version as the client code isn't really meant to adapt
to such build-time constraints.

Committed now. Not yet thoroughly degbugged etc, but at least the funtionality
is now present.

  They introduce known_host support for SSH keys to libcurl. See docs for
  details.

  (https://bugzilla.novell.com/523919). When looking at the code, I found
  that also the ptr pointer can leak.

  http://curl.haxx.se/bug/view.cgi?id=2818950