asyn-ares: Don't blank ares servers if none configured.

Best to just let c-ares use it's defaults if none are configured
in (lib)curl.

Signed-off-by: Ben Greear <greearb@candelatech.com>
curl_multi_wait: set revents for extra fds

Pass back the revents that happened for the user-provided file
descriptors.
configure: fix 'subdir-objects' distclean related issue

See XC_AMEND_DISTCLEAN comments for details.
xc-am-iface.m4: comments refinement
Reinstate "WIN32 MemoryTracking: track wcsdup() _wcsdup() and _tcsdup() usage".

This reverts commit 7ed25cc, reinstating commit 8ec2cb5.

As of 18-jul-2013 we still do have code in libcurl that makes use of these
memory functions. Commit 8ec2cb5 comment still applies and is yet valid.

These memory functions are solely used in Windows builds, so all related
code is protected with '#ifdef WIN32' preprocessor conditional compilation
directives.

Specifically, wcsdup() _wcsdup() are used when building a Windows target with
UNICODE and USE_WINDOWS_SSPI preprocessor symbols defined. This is the case
when building a Windows UNICODE target with Windows native SSL/TLS support
enabled.

Realizing that wcsdup() _wcsdup() are used is a bit tricky given that usage
of these is hidden behind _tcsdup() which is MS way of dealing with code
that must tolerate UNICODE and non-UNICODE compilation. Additionally, MS
header files and those compatible from other compilers use this preprocessor
conditional compilation directive in order to select at compilation time
whether 'wide' or 'ansi' MS API functions are used.

Without this code, Windows build targets with Windows native SSL/TLS support
enabled and MemoryTracking support enabled misbehave in tracking memory usage,
regardless of being a UNICODE enabled build or not.
CURLOPT_XFERINFOFUNCTION: introducing a new progress callback

CURLOPT_XFERINFOFUNCTION is now the preferred progress callback function
and CURLOPT_PROGRESSFUNCTION is considered deprecated.

This new callback uses pure 'curl_off_t' arguments to pass on full
resolution sizes. It otherwise retains the same characteristics: the
same call rate, the same meanings for the arguments and the return code
is used the same way.

The progressfunc.c example is updated to show how to use the new
callback for newer libcurls while supporting the older one if built with
an older libcurl or even built with a newer libcurl while running with
an older.
WIN32 MemoryTracking: require UNICODE for wide strdup code support
Makefile.b32: Borland makefile adjustments. Tested with BCC 5.5.1