GLib 2.16 was released more than 4 years ago.  Let's remove some cruft
from the glib_compat.h header, and avoid new cruft to it.

Ensure that WINVER is defined early enough, so other system headers
won't fall back to their default value.  Specifically, this solves a
build failure (-Werror) with mingw-w64 ("WINVER redefined").

In a C file, that is too late, because _mingw.h defaults to 0x0502,
and ours would be illegal redefintion.

Allow port specification in "bind_to_address" settings.

Wrap close(), use closesocket() on WIN32/WinSock.

The server_socket library (used by the httpd output plugin) didn't
check for WIN32, that's fixed now.

If a connected host disappears without our knowledge, as can happen over
wireless or a hibernating machine, we continue to hold the port open waiting
for messages. Because we never try to send anything down this now-broken
pipe, the connection will sit idle taking up a slot in our allowed incoming
connections list.

If enough of these happen, an unintended Denial of Service takes place,
where all connection slots are filled with now-broken, never ending
connections. Setting the TCP keepalive option at least allows these to time
out after the default two hours, which is sufficient in the non-malicious
case.
Signed-off-by: Dan McGee <dan@archlinux.org>

When you pass the flag AI_ADDRCONFIG to getaddrinfo(), it does not
consider address families on the loopback device.  When run on a
machine without an external network card, just with "lo", it was
unable to look up any address.