This appears to work and the event handler *should* work on other
event types already.

Note, this is *nix-only due to the use of poll().  select() will
need to be used for Windows to keep XP compatability.

socket_readable() returns TRUE if recv() will not block if called
on the specified socket.

socket_writable() returns TRUE if send() will not block if called
on the specified socket.

socket_recvdone() returns TRUE if all data has been recv()ed an
the socket is closed.

"will not block" includes "will return an error".

This matches the three main use-cases for select() of a single socket
in Synchronet.

Use them in the SyncTERM RLogin stuff so they can be tested easily.

There has been a sighting of Synchronet exceeding FD_SETSIZE sockets.
This means select() is of less use and we need to start migrating to
either poll() or platform-specific methods to achieve the same end.

This commit is mostly to check that poll() builds on Win32 and that
it actually works.

xp_inet_pton() now sets the socket errno value, doing as instructed by the TODO.

Rename the portable inet_pton() to xp_inet_pton() and define a wrapper macro (for all Widows builds) to use it instead of inet_pton() as not all supported Windows systems (e.g. WinXP) have an inet_pton() implementation.

This allows the HAProxy mod to be re-enabled by default without preventing executing on WinXP.

Sorry guys. :(

Needed by MinGW32... we'll see if MSVC needs it as well soon.

that support large file offsets (e.g. 64-bit Linux).
Considered returning ssize_t (like sendfile does), but opted for off_t. Could
be convinced otherwise.

descriptions in bind failure error messages in a cross-platform
(i.e. WinSock-compatible) manner.

Hopfully this doesn't break the Borland or Watcom (?!) builds.

address (family and address value, ignoring ports and other fields).

conventions when using the ws2tcpip.h that comes with Borland (sigh).

Fix inet_addrtop() for Win32.

from a generic struct sockaddr.

Add a xpms_add_list() for adding a str_list_t full of host[:port] definitions
for when reading a str_list_t from the INI file of interfaces to listen on.

_FILE_OFFSET_BITS=64, and use fseeko() and ftello() for 64-bit offset support
(instead of fseek() and ftell()) - also redefine off_t on Win32 to int64_t and
removed filelen_t and fileoff_t typedefs (use off_t instead).

is defined (for MSVC only, currently).

by properly const-ifying the appropriate functions and variables.

Not yet tested on Win32