XIM: Fix race on focus change: set 'FABRICATED' only when keyev filters in place.

When synthesized key events are sent on commit XIM sets the 'fabricated'
flag so that the keypress handler knows that these were not real events.
This also happens when committing due to the loss of focus. However in this
case the keypress/release filters which consume and unset this flag are no
longer in the filter chain.
So the flag is erronously set when a real keyboard event is received after
focus has been regained. So the first event is wrongly treated as a
fabricated key in the keypress handler which will at the same time reset
the flag so the second key event is treated correctly.
This fix only sets the flag when at least one of the keyboard filters is in
place.
How to reproduce this bug: run scim, choose a Japanese input method start
two instances of xterm: start typing in one xterm (this should pop up an
IM window). Without comitting (hitting 'enter') move focus to the other
xterm, then move focus back. Start typing again. The first character will
be committed immediately without popping up an input window.
With this fix this behavior is gone.

See also: https://bugzilla.novell.com/show_bug.cgi?id=239698

Signed-off-by: Egbert Eich <eich@freedesktop.org>
XIM: Fix sync problem on focus change.

XSetICFocus() and XUnsetICFocus() are both asynchronous events.
This is a pretty stupid idea: those functions may undo certain
settings on the client side for which requests from the server
may still be in the queue unprocessed. Thus things may be set
in the wrong order ie instead of set -> unest it will be unset -> set.
Moreover there is no way for either the client or the server to
cause the event queue to be flushed - which is pretty bad as
XIM is bidirectional.
The scenario is as follows:
Two ICs are created:
        ic1 = XCreateIC(im,
            XNInputStyle, XIMPreeditCallbacks | XIMStatusCallbacks,
            XNClientWindow, window,
            XNPreeditAttributes, preedit_attr,
            XNStatusAttributes, status_attr,
            NULL);
        ic2 = XCreateIC(im, XNInputStyle,
                       XIMPreeditNothing | XIMStatusNothing,
                       XNClientWindow, window, NULL);
Then the focus is removed from ic2:
        XUnsetICFocus(ic2);
If SCIM is used as the input server it will send a bunch of requests
following an XCreateIC(). One of the requests registers a key release
filter. XUnsetICFocus() unsets both key press and release filters.
Since it is asynchronous, the input server requests to register key
press and release filters may not have been processed, when XUnsetICFocus()
is called. Since there is no explicite way for client programs to enforce
the request queue to be flushed explicitely before an X[Set/Unset]ICFocus()
call it would be safest to make those two calls synchronous in the sense
that they ensure the request queue has been handled before they execute.
The easiest way to do this from Xlib is thru a call to XGetICValues()
which sends a request to the server and subsequently reads the queue
from the server to the client. This will cause all outstanding requests
in the queue to be read and handled.
This is an ugly hack and this could be fixed directly in the client,
however it seems to be easier to fix Xlib than to fix numerous clients.
This problem arose since there is no well documented way how to handle
and synchronize XIM requests and not all input servers send requests
when an IC is created.
This has been discussed extensively in:
 https://bugzilla.novell.com/show_bug.cgi?id=221326

Signed-off-by: Egbert Eich <eich@freedesktop.org>