qdii@ciruella ~ $ gdb --args /usr/bin/gnome-panel-renamed --sync
GNU gdb (Gentoo 7.2 p1) 7.2
Copyright (C) 2010 Free Software Foundation, Inc.
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This GDB was configured as "x86_64-pc-linux-gnu".
For bug reporting instructions, please see:
<http://bugs.gentoo.org/>...
Reading symbols from /usr/bin/gnome-panel-renamed...(no debugging symbols found)...done.
(gdb) break gdk_x_error
Function "gdk_x_error" not defined.
Make breakpoint pending on future shared library load? (y or [n]) r
Please answer y or [n].
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (gdk_x_error) pending.
(gdb) r
Starting program: /usr/bin/gnome-panel-renamed --sync
[Thread debugging using libthread_db enabled]
[New Thread 0x7fffec718700 (LWP 12292)]
[New Thread 0x7fffdc4f2700 (LWP 12371)]

Breakpoint 1, 0x00007ffff6672de0 in gdk_x_error () from /usr/lib/libgdk-x11-2.0.so.0
(gdb) bt
#0  0x00007ffff6672de0 in gdk_x_error () from /usr/lib/libgdk-x11-2.0.so.0
#1  0x00007ffff461698c in _XError () from /usr/lib/libX11.so.6
#2  0x00007ffff46136b7 in ?? () from /usr/lib/libX11.so.6
#3  0x00007ffff4613705 in ?? () from /usr/lib/libX11.so.6
#4  0x00007ffff4613cc0 in _XReply () from /usr/lib/libX11.so.6
#5  0x00007ffff460f603 in XSync () from /usr/lib/libX11.so.6
#6  0x00007ffff460f7bb in ?? () from /usr/lib/libX11.so.6
#7  0x00007ffff460c702 in XReparentWindow () from /usr/lib/libX11.so.6
#8  0x00007ffff6682ae2 in gdk_window_x11_reparent () from /usr/lib/libgdk-x11-2.0.so.0
#9  0x00007ffff6650975 in gdk_window_reparent () from /usr/lib/libgdk-x11-2.0.so.0
#10 0x00007ffff6a52d48 in _gtk_plug_add_to_socket () from /usr/lib/libgtk-x11-2.0.so.0
#11 0x00007ffff6a95c78 in _gtk_socket_add_window () from /usr/lib/libgtk-x11-2.0.so.0
#12 0x0000000000475984 in ?? ()
#13 0x00007ffff5f03d9c in complete_in_idle_cb () from /usr/lib/libgio-2.0.so.0
#14 0x00007ffff4b56052 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#15 0x00007ffff4b5a718 in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#16 0x00007ffff4b5ac25 in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#17 0x00007ffff6a16007 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#18 0x0000000000426bac in main ()
(gdb)