Im new at Qt and I'm struggling with libGLViewer. Here is my issue: when finished the first sample program of libGLViewer I got this error, and I really dont know what to do to fix it. I'm looking forward for an answer.

Error:

Makefile.Debug:132: warning: overriding commands for target `debug/main.o'
Makefile.Debug:126: warning: ignoring old commands for target `debug/main.o'
Here is the code too:

simplerviewer.h

Qt Code: 
  1. #ifndef SIMPLEVIEWER_H
  2. #define SIMPLEVIEWER_H
  3.  
  4. #include <QGLViewer/qglviewer.h>
  5.  
  6. class Viewer : public QGLViewer
  7. {
  8. protected :
  9.   virtual void draw();
  10.   virtual void init();
  11.   virtual QString helpString() const;
  12. };
  13.  
  14. #endif // SIMPLEVIEWER_H
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simplerviewer.cpp

Qt Code: 
  1. #include "simpleViewer.h"
  2.  
  3. using namespace std;
  4.  
  5. // Draws a spiral
  6. void Viewer::draw()
  7. {
  8.   const float nbSteps = 200.0;
  9.  
  10.   glBegin(GL_QUAD_STRIP);
  11.   for (int i=0; i<nbSteps; ++i)
  12.     {
  13.       const float ratio = i/nbSteps;
  14.       const float angle = 21.0*ratio;
  15.       const float c = cos(angle);
  16.       const float s = sin(angle);
  17.       const float r1 = 1.0 - 0.8f*ratio;
  18.       const float r2 = 0.8f - 0.8f*ratio;
  19.       const float alt = ratio - 0.5f;
  20.       const float nor = 0.5f;
  21.       const float up = sqrt(1.0-nor*nor);
  22.       glColor3f(1.0-ratio, 0.2f , ratio);
  23.       glNormal3f(nor*c, up, nor*s);
  24.       glVertex3f(r1*c, alt, r1*s);
  25.       glVertex3f(r2*c, alt+0.05f, r2*s);
  26.     }
  27.   glEnd();
  28. }
  29.  
  30. main.cpp
  31.  
  32. void Viewer::init()
  33. {
  34.   // Restore previous viewer state.
  35.   restoreStateFromFile();
  36.  
  37.   // Opens help window
  38.   help();
  39. }
  40.  
  41. QString Viewer::helpString() const
  42. {
  43.   QString text("<h2>S i m p l e V i e w e r</h2>");
  44.   text += "Use the mouse to move the camera around the object. ";
  45.   text += "You can respectively revolve around, zoom and translate with the three mouse buttons. ";
  46.   text += "Left and middle buttons pressed together rotate around the camera view direction axis<br><br>";
  47.   text += "Pressing <b>Alt</b> and one of the function keys (<b>F1</b>..<b>F12</b>) defines a camera keyFrame. ";
  48.   text += "Simply press the function key again to restore it. Several keyFrames define a ";
  49.   text += "camera path. Paths are saved when you quit the application and restored at next start.<br><br>";
  50.   text += "Press <b>F</b> to display the frame rate, <b>A</b> for the world axis, ";
  51.   text += "<b>Alt+Return</b> for full screen mode and <b>Control+S</b> to save a snapshot. ";
  52.   text += "See the <b>Keyboard</b> tab in this window for a complete shortcut list.<br><br>";
  53.   text += "Double clicks automates single click actions: A left button double click aligns the closer axis with the camera (if close enough). ";
  54.   text += "A middle button double click fits the zoom of the camera and the right button re-centers the scene.<br><br>";
  55.   text += "A left button double click while holding right button pressed defines the camera <i>Revolve Around Point</i>. ";
  56.   text += "See the <b>Mouse</b> tab and the documentation web pages for details.<br><br>";
  57.   text += "Press <b>Escape</b> to exit the viewer.";
  58.   return text;
  59. }
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Qt Code: 
  1. #include "simpleViewer.h"
  2. #include <qapplication.h>
  3.  
  4. int main(int argc, char** argv)
  5. {
  6.   // Read command lines arguments.
  7.   QApplication application(argc,argv);
  8.  
  9.   // Instantiate the viewer.
  10.   Viewer viewer;
  11.  
  12. #if QT_VERSION < 0x040000
  13.   // Set the viewer as the application main widget.
  14.   application.setMainWidget(&viewer);
  15. #else
  16.   viewer.setWindowTitle("simpleViewer");
  17. #endif
  18.  
  19.   // Make the viewer window visible on screen.
  20.   viewer.show();
  21.  
  22.   // Run main loop.
  23.   return application.exec();
  24. }
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Please, it would be nice some answers. Thnx!