Test suite support for RTSP

Make Curl_pop3_write() additionally truncate trailing POP3_EOB from received
string buffer, otherwise Curl_client_write() call with zero size would write
to the end of string buffer including matched POP3_EOB.

WIN32 fix, _beginthreadex() may return either 0 or -1L upon failure

fix errno usage for WIN32 builds

fix printf-style format strings

Chris Conroy fixed test #568 issues with carriage returns

RTSP followup fix. Both the pipelined and non-pipelined case need to
check for (excess > 0 && !k->ignorebody).

  check for broken connections like ares_process() did. Based on that, I
  merged the two functions into a single generic one with two front-ends.

fix printf-style format strings

Use 'size_t' for GETNAMEINFO_TYPE_ARG2 definition for VMS.

http://curl.haxx.se/mail/lib-2009-12/0293.html

portability fix

fix printf-style format strings

Known bug #64 fixed by Constantine Sapuntzakis and Joshua Kwan in 7.20.0

Chris Conroy provided first RTSP tests

RTSP tests disabled until test harness RTSP support is updated

Chris Conroy's RTSP followup fixes

mention asynchronous DNS lookups enhancements

Restore normal operation:

  c-ares is only enabled when specifically requested.

  Consequently, c-ares default setting is disabled.

fix c-ares assumed check being skipped

fix compiler warning

fix LDFLAGS preservation in CURL_CHECK_LIB_ARES

is now a very long time ago

  proxy that cannot be resolved when using c-ares. This matches the behaviour
  when not using c-ares.

fix compiler warning

HAVE_GETADDRINFO_THREADSAFE definition for non-configure win32 builds

add inclusion of curl_memory.h