emacs --daemon and GDK default display

[Ulrich Mueller <ulm@gentoo.org>]

Hi, at Gentoo we've got a report on a segmentation fault with 23.0.91:
<http://bugs.gentoo.org/259891>

   1. install libcanberra and emacs (--with-x-toolkit=gtk)
   2. run "emacs -Q --daemon"
   3. under GNOME, run "emacsclient -c" (exit with C-x 5 0)
   4. run "emacsclient -c" again, and emacs will segfault

It happens because there is no GDK default display when the display
for the second client frame is opened (xg_display_open), and
libcanberra fails to check for that case.

While I think that the blame is with libcanberra, I'm confused about
the fact that the segfault only happens during the second request from
a client. Does it mean that there is a GDK default display at the time
of the first request, but not for the second one? Why?

Could somebody shed some light on the issue?

Ulrich