CARES_HAVE_ARES_FREE_DATA as an indication of function availability.

to return a linked lists of results. These were also modified to internally
use the ares_data memory struct and as such its result must be free'ed with
ares_free_data().

applications to free memory allocated and returned by some c-ares funtions.

calloc() and realloc() function calls.

  end up with entries that wouldn't time-out:

  1. Set up a first web server that redirects (307) to a http://server:port
     that's down
  2. Have curl connect to the first web server using curl multi

  After the curl_easy_cleanup call, there will be curl dns entries hanging
  around with in_use != 0.

  (http://curl.haxx.se/bug/view.cgi?id=2891591)

  its pkg-config file.  So -Wl stuff ended up in the .pc file, which is really
  bad, and breaks if there are multiple -Wl in our LDFLAGS (which are in
  PTXdist). bug #2893592 (http://curl.haxx.se/bug/view.cgi?id=2893592)

  (and in particular the list of required libraries) even if a path is given
  as argument to --with-ssl

getaddrinfo is fully thread safe on solaris versions which
implement the function even when h_errno is not a macro.

The h_errno macro test now only done on systems for which there
is no hard coded knowledge about getaddrinfo's thread safeness.

Client certificate ENG file type requires OpenSSL 0.9.7 or newer

Remove files generated on previous buildconf/configure run

Add a couple of renamed files to the removal list

Remove enable-thread / disable-thread configure option. These were only placebo
options. The library is always built as thread safe as possible on every system.

Added '--configure' option to curl-config to display original configure arguments when curl was built

Refactor how preprocessor symbol _THREAD_SAFE definition is done.

OpenSSL 0.9.7 or newer required for ENGINE_CTRL_GET_CMD_FROM_NAME definition

  --with-nss is set but not "yes".

  I think we can still improve that to check for pkg-config in that path etc,
  but at least this patch brings back the same functionality we had before.

  the client certificate. It also disable the key name test as some engines
  can select a private key/cert automatically (When there is only one key
  and/or certificate on the hardware device used by the engine)

- Constantine Sapuntzakis provided the fix that ensures that an SSL connection
  won't be reused unless protection level for peer and host verification match.

knowledge says the contrary or h_errno is not defined.

- Constantine Sapuntzakis reported that Darwin 6.0 a.k.a. MAC OS X 10.2
  and newer have a threadsafe getaddrinfo.

- Fix Dragonfly BSD triplet detection.

- In case the hard-coded knowledge says that getaddrinfo is threadsafe,
  an additional check is done to verify that h_errno is also defined.
  If h_errno isn't defined, we finally assume that it isn't threadsafe.
  Jamie Lokier provided the inspiration for this extra check.

Add some comments to better understand what the regex's pretend to achieve.

No need for a separate variable ndns.

The memory leak detection will detect code that fails to release a dns reference.

The DEBUGASSERT will detect code that releases too many references.

  a broken TLS server. However it does not happen if SSL version is selected
  manually. The approach was originally taken from PSM. Kaspar Brand helped me
  to complete the patch. Original bug reports:
  https://bugzilla.redhat.com/525496
  https://bugzilla.redhat.com/527771

  closed NSPR descriptor. The issue was hard to find, reported several times
  before and always closed unresolved. More info at the RH bug:
  https://bugzilla.redhat.com/534176