[PATCH] xwininfo: do not segfault on IO error

[Adam Jackson]

On Tue, 2015-01-06 at 11:57 +0100, Olivier Fourdan wrote:
> If the connection to the X server is lost while waiting for
> the user to select a window interactively, xwininfo segfaults.
> 
> This is a regression introduced with the port to XCB, because
> xcb_wait_for_event() can return NULL in case of an IO error and
> xwininfo does not check for the actual returned value.

Reviewed-by: Adam Jackson <ajax at redhat.com>

- ajax