autoconf 2.57 usage (which is the version you have specified as the minimum
  version). It's a minor change but it does clean up some warnings with newer
  autoconf (specifically 2.62).

  ares_expand_string.c

compiled with errors. This behaviour is needed for autoconf macros which
rely on the ability to compile with or without errors, and is safer than
xlc's default of failing only upon severe errors.

added get_ver.awk since c-ares is a standalone project, and should therefore also compile when cURL is absent.

fixed comments; fixed INSTDIR define, simplified rules;
changed to use get_ver.awk in current dir rather than the curl one.

and makes wrong asumptions of build target when it isn't specified. So,
if no build target has been defined we will target WinXP when building
with MSVC 9.0 (VS2008).

name from an IPv4-address or host-name. Using the service of
countries.nerd.dk.

link any executables when doing debug builds since they kind of assume
symbols provided by libcurl, but it also wrongly included acountry.c

define 's6_addr' as a macro.

/dev/urandom when built cross-compiled as then the script cannot check for
it.

/etc/hosts file, pointed out by Erik Kline:
http://daniel.haxx.se/projects/c-ares/mail/c-ares-archive-2007-11/0027.shtml

warnings. Pointed out by Robin Cornelius.