code:

#include <KApplication>
#include <KAboutData>
#include <KCmdLineArgs>
#include <kdesu/client.h>

#include "kgrubeditor.h"

int main( int argc, char **argv )
{	
	KApplication app;
	KGRUBEditor *main_window = new KGRUBEditor;
	KDESu::KDEsuClient client;
	
	if ( app.isSessionRestored() )
	{
		RESTORE( KGRUBEditor );
	}
	else
	{
		main_window->show();
	}

	return app.exec();
}

error:

phobos@phobos-desktop:~/Development/build/KGRUBEditor$ run
-- Found Qt-Version 4.3.2
-- Found X11: /usr/lib/libX11.so
-- Found KDE 4.0 include dir: /usr/lib/kde4/include
-- Found KDE 4 library dir: /usr/lib/kde4/lib
-- Found KDE4 kconfig_compiler preprocessor: /usr/lib/kde4/bin/kconfig_compiler
-- Found KDE4 automoc: /usr/lib/kde4/bin/kde4automoc
-- Configuring done
-- Generating done
-- Build files have been written to: /home/phobos/Development/build/KGRUBEditor
[ 10%] Generating kgrubeditor_automoc.cpp
Scanning dependencies of target kgrubeditor
[ 20%] Building CXX object CMakeFiles/kgrubeditor.dir/kgrubeditor_automoc.o
[ 30%] Building CXX object CMakeFiles/kgrubeditor.dir/src/main.o
Linking CXX executable kgrubeditor
CMakeFiles/kgrubeditor.dir/src/main.o: In function `main':
/home/phobos/Development/svn/kgrubeditor/src/main.cpp:37: undefined reference to `KDESu::KDEsuClient::KDEsuClient()'
/home/phobos/Development/svn/kgrubeditor/src/main.cpp:48: undefined reference to `KDESu::KDEsuClient::~KDEsuClient()'
collect2: η ld επέστρεψε κατάσταση εξόδου 1
make[2]: *** [kgrubeditor] Error 1
make[1]: *** [CMakeFiles/kgrubeditor.dir/all] Error 2
make: *** [all] Error 2
phobos@phobos-desktop:~/Development/build/KGRUBEditor$