Integrating xwinclip support

[Harold L Hunt]

> Can you make it still be an X client? If you can check that there are >1
> clients avaiable, and detach + return when there aren't...
> 
> Rob

The problem is that XNextEvent () is a blocking function, just like Win32's 
GetMessage () function.  The problem here is when the X Server exits or 
resets while XNextEvent () is blocking... in that case our X Client 
(xwinclip) gets no notification that the X Server is exiting or resetting and 
Xlib calls exit () for the X Client.  I'm trying to find a way around that... 
primarily by seeing if there is a way to get notification before Xlib calls 
exit (), that way we could close down the connection in a proper fashion.

Harold