How to debug Pidgin

[A.TNG]

Hi,

I'm a newbie to Pidgin. I already compile Pidgin's source code by
myself and make nullclient run.

My env is Windows XP + Cygwin(gcc 3.4.4+ gdb 6.5.50).

I use following configure parameters:
./configure --prefix=/usr/local/pidgin-2.4.2 --disable-screensaver
--disable-gtkspell --disable-gstreamer --disable-meanwhile
--disable-avahi --disable-dbus --with-dynamic-prpls=jabber
--disable-perl --enable-debug
The last parameter "--enable-debug" should enable debug.

But, When I run "gdb nullclient" and get the prompt and use "l" to
list source code, I get nothing.

Please check following output:

$ gdb example/nullclient.exe
GNU gdb 6.5.50.20060706-cvs (cygwin-special)
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-pc-cygwin"...(no debugging symbols found)

(gdb) list
No symbol table is loaded.  Use the "file" command.
(gdb) l
No symbol table is loaded.  Use the "file" command.

How can I debug Pidgin?

Thanks for help.
-- 

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Best Regard,
Tang, Jiyu