is non-NULL before we FD_CLR

both to occur

several functions (write_tcp_data, read_tcp_data, read_udp_packets) so that
if it fails and the socket is closed the following code doesn't try to use
the file descriptor.

TCP is used since there are several edge cases where it still makes sense.

He also made recent Microsoft compilers use _strdup() instead of strdup().

specific sockets and thus avoiding select() and associated functions/macros.
This function will be used by upcoming libcurl releases for this very
reason. It also made me export the ares_socket_t type in the public ares.h
header file, since ares_process_fd() uses that type for two of the arguments.

since it's already included through "setup.h".

Check for lowercase 'bool' type at configuration stage. If not available
provide a suitable replacement with a type definition of 'unsigned char'
in setup_once.h

Move definitions of TRUE and FALSE to setup_once.h

to verify winsock API availability.

 o made ares_version.h use extern "C" for c++ compilers
 o fixed compiler warnings in ares_getnameinfo.c
 o fixed a buffer position init for TCP reads

UDP even when a poll(2) or select(2) suggest otherwise.

c-ares call a callback on socket state changes. A better way than the
ares_getsock() to get full control over the socket state.

rearrangement in ares_process.c.

  Make UDP sockets non-blocking. I've confirmed that at least on Linux 2.4 a
  read event can come back from poll() on a valid SOCK_DGRAM socket but
  recv(2) will still block. This patch doesn't ignore EAGAIN in
  read_udp_packets(), though maybe it should. (This patch was edited by Daniel
  Stenberg and a new configure test was added (imported from curl's configure)
  to properly detect what non-blocking socket approach to use.)

X.

sets the required HAVE_xx defines for non-DOS/Win targets.

Basically in loops like handle_errors(), 'query->next' was assigned a local
variable and then query was referenced after the memory was freed by
next_server(). I've changed that so next_server() and end_query() returns the
next query. So callers should use this ret-value.

The next problem was that 'server->tcp_buffer_pos' had a random value at entry
to 1st recv() (luckily causing Winsock to return ENOBUFS).

I've also added a ares_writev() for Windows to streamline the code
a bit more.

  check for ssize_t to make it possible to use that when receiving the send()
  error code. This is necessary to prevent compiler warnings on some systems.

- Made configure create config.h, and all source files now include setup.h that
  might include the proper config.h (or a handicrafted alternative).

- Switched to 'ares_socket_t' type for sockets in ares, since Windows don't
  use 'int' for that.

- automake-ified and libool-ified c-ares. Now it builds libcares as a shared
  lib on most platforms if wanted. (This bloated the size of the release
  archive with another 200K!)

- Makefile.am now uses Makefile.inc for the c sources, h headers and man
  pages, to make it easier for other makefiles to use the exact same set of
  files.

- Adjusted 'maketgz' to use the new automake magic when building distribution
  archives.

Windows.