where is the panel-applet.h

[root <lanyangzhan sina com>]

-- I want write a simple applet, the output is the following:
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[root services gnome-dvp]# gcc applet.c -o applet `gnome-config --cflags
--libs gnome glib`
applet.c:2:26: panel-applet.h: no such file 
applet.c: In function `main':
applet.c:10: warning: assignment makes pointer from integer without a
cast
applet.c:6: warning: return type of `main' is not `int'
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how can I use the gcc command? Can some one help me, thanks
lanyz