ofAppEGLWindow on Linux "undefined reference" error

Hello,
this is my code.

#include “ofMain.h”
#include “ofApp.h”
#include “ofAppEGLWindow.h”

//========================================================================
int main( ){
ofAppEGLWindow::Settings settings;
settings.width = 1024;
settings.height = 768;
settings.setPosition(ofVec2f(0,0));
settings.screenNum = 1;
ofCreateWindow(settings);
ofRunApp(new ofApp());
}

I would use ofAppEGLWindow in my example.
But I get this error:
main.cpp :(. text.startup + 0xE2): undefined reference to “Settings ofAppEGLWindow :: :: Settings ()”

where am I wrong?