c-ares libraries in debug and release flavours.

Additionally each of the three sample programs is built against
each of the four possible c-ares libraries, generating all this
a total number of 12 executables and 4 libraries.

  in non-blocking mode.

curl.h, adjusting auto-makefiles include path, to enhance portability to
OS's without an orthogonal directory tree structure such as OS/400.

  wrong percentage for small files, most notable for <1000 bytes and could
  easily end up showing more than 100% at the end. It also didn't show any
  percentage, transfer size or estimated transfer times when transferring
  less than 100 bytes.

tarball

moved to 7.19.8. I removed the bugs already in KNOWN_BUGS (but they should
of course still get fixed).

Added three recent bugs. 7.19.8 is targetted to get shipped in Janurary 2010

  CURLINFO_SIZE_DOWNLOAD (the -w variable size_download) didn't work when
  getting data from ldap!

c-ares with --enable-curldebug uses memdebug.h from libcurl's lib subdirectory.

memdebug.h needs access to libcurl's setup.h from libcurl's lib subdirectory
and also needs access to libcurl's generated curl_config.h

Undo old temporary change once used for testing purposes

  download was 0 bytes, as libcurl would then return the size as unknown (-1)
  and not 0. I wrote a fix and test case 566 to verify it.

Symbol hiding configure options renamed to the hopefully less ambiguous
--enable-symbol-hiding and --disable-symbol-hiding as well as related
macro names and some internal variables used for them.

Related configuration file preprocessor symbols named to
CARES_SYMBOL_HIDING and CARES_SYMBOL_SCOPE_EXTERN.

(http://curl.haxx.se/bug/view.cgi?id=2884561) but it seems to work for me...

  auth is used, as it caused a crash. I failed to repeat the issue, but still
  made a change that now forces the TCP connection used for a freed SCP
  session to get closed and not be re-used.

  POST using a read callback, with Digest authentication and
  "Transfer-Encoding: chunked" enforced.  I would then cause the first request
  to be wrongly sent and then basically hang until the server closed the
  connection. I fixed the problem and added test case 565 to verify it.

Fix two typos.