Comment 4 for bug 129106

I came up with a change that appears to fix it. But I don't know
the vim code and X enough to say whether it's the correct way
to fix it. But at least, it no longer crashes.

I only added a call to test_x11_window(x11_display) at line 1698 in os_unix.c:

***************
*** 1695,1701 ****
      int retval = FALSE;
      Status status;

! if (get_x11_windis() == OK)
      {
        /* Get window/icon name if any */
        if (get_title)
--- 1695,1701 ----
      int retval = FALSE;
      Status status;

! if (get_x11_windis() == OK && test_x11_window(x11_display) == OK)
      {
        /* Get window/icon name if any */
        if (get_title)

I will post the patch to the vim_dev mailing list for review.