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.)
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.
When using it, we now set the include path to better find the devel curl
headers, and we check for the socklen_t type since the curl memdebug stuff
needs it.
