title: CMake is dropping the item c++
body: <p>I work on windows with QtCreator .I try to use freeglut/opengl2 all libs have been build and install properly
   But have undefined references to all glut components certainly due to : Targets may link only to libraries.  CMake is dropping the item.</p>
  
  <p>here my CMakelists.txt</p>
  
  <pre><code>project(Projet_AIN CXX)
  cmake_minimum_required(VERSION 2.8)
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 ")
  find_package(GLUT   REQUIRED)
  find_package(GLEW   REQUIRED)
  find_package(OpenGL REQUIRED)
  
  include_directories(${GLEW_INCLUDE_DIR}
                      ${GLUT_INCLUDE_DIR}
                      ${OpenGL_INCLUDE_DIR})
  
  link_directories(${GLEW_LIBRARIES_DIR}
                   ${GLUT_LIBRARY_DIR}
                   ${OpenGL_LIBRARY_DIR})
  
  add_definitions(${OpenGL_DEFINITIONS}
                  ${GLEW_DEFINITIONS}
                  ${GLUT_DEFINITIONS})
  
  
  
  set(EXECUTABLE_OUTPUT_PATH bin/${CMAKE_BUILD_TYPE})
  file(
      GLOB
      SOURCE_FILES
      include/*.hpp
      src/*.cpp
  )
  
  
  add_executable(
          ${PROJECT_NAME}
          ${SOURCE_FILES}
  )
  target_link_libraries(${PROJECT_NAME}
                    ${OPENGL_LIBRARY}
                    ${GLEW_LIBRARY}
                    ${GLUT_LIBRARY}
                    )
  </code></pre>
  
  <p>CMake output:</p>
  
  <pre><code>Running "C:\cmake\bin\cmake.exe C:/Users/Thibaut/Documents/Projet_Raffin "-GCodeBlocks - MinGW Makefiles" "-DCMAKE_BUILD_TYPE:STRING=Debug" "-DCMAKE_CXX_COMPILER:STRING=C:/MinGW/bin/g++.exe" "-DCMAKE_C_COMPILER:STRING=C:/MinGW/bin/gcc.exe" "-DCMAKE_PREFIX_PATH:STRING=%{Qt:QT_INSTALL_PREFIX}" "-DGLEW_INCLUDE_DIR:PATH=C:/Program Files (x86)/glew/include" "-DGLEW_LIBRARY:FILEPATH=C:/Program Files (x86)/glew/lib" "-DGLUT_INCLUDE_DIR:PATH=C:/Program Files (x86)/freeglut/include" "-DGLUT_glut_LIBRARY:FILEPATH=C:/Program Files (x86)/freeglut/lib" "-DQT_QMAKE_EXECUTABLE:STRING="" in C:\Users\Thibaut\Documents\build-Projet_Raffin-Kat-Debug.
  -- Configuring done
  WARNING: Target "Projet_AIN" requests linking to directory "C:/Program Files (x86)/glew/lib".  Targets may link only to libraries.  CMake is dropping the item.
  WARNING: Target "Projet_AIN" requests linking to directory "C:/Program Files (x86)/freeglut/lib".  Targets may link only to libraries.  CMake is dropping the item.
  -- Generating done
  -- Build files have been written to: C:/Users/Thibaut/Documents/build-Projet_Raffin-Kat-Debug
  </code></pre>
  
  <p>Make output:</p>
  
  <pre><code>14:26:39: Exécution des étapes pour le projet Projet_AIN...
  14:26:39: Running CMake in preparation to build...
  14:26:39: Débute : "C:\cmake\bin\cmake.exe" --build . --target all
  [ 50%] Building CXX object CMakeFiles/Projet_AIN.dir/src/main.cpp.obj
  [100%] Linking CXX executable bin\Debug\Projet_AIN.exe
  CMakeFiles\Projet_AIN.dir/objects.a(main.cpp.obj): In function `glutInit_ATEXIT_HACK':
  C:/PROGRA~2/freeglut/include/GL/freeglut_std.h:637: undefined reference to `__imp___glutInitWithExit'
  CMakeFiles\Projet_AIN.dir/objects.a(main.cpp.obj): In function `glutCreateWindow_ATEXIT_HACK':
  C:/PROGRA~2/freeglut/include/GL/freeglut_std.h:639: undefined reference to `__imp___glutCreateWindowWithExit'
  CMakeFiles\Projet_AIN.dir/objects.a(main.cpp.obj): In function `glutCreateMenu_ATEXIT_HACK':
  C:/PROGRA~2/freeglut/include/GL/freeglut_std.h:641: undefined reference to `__imp___glutCreateMenuWithExit'
  CMakeFiles\Projet_AIN.dir/objects.a(main.cpp.obj): In function `action_timer(int)':
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:30: undefined reference to `__imp_glutPostRedisplay'
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:31: undefined reference to `__imp_glutTimerFunc'
  CMakeFiles\Projet_AIN.dir/objects.a(main.cpp.obj): In function `RenderScene()':
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:71: undefined reference to `__imp_glutWireTeapot'
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:73: undefined reference to `__imp_glutSwapBuffers'
  CMakeFiles\Projet_AIN.dir/objects.a(main.cpp.obj): In function `callback_Keyboard(unsigned char, int, int)':
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:80: undefined reference to `__imp_glutLeaveMainLoop'
  CMakeFiles\Projet_AIN.dir/objects.a(main.cpp.obj): In function `InitializeGL()':
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:113: undefined reference to `__imp_glutTimerFunc'
  CMakeFiles\Projet_AIN.dir/objects.a(main.cpp.obj): In function `GlewInit()':
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:118: undefined reference to `__imp_glewInit'
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:122: undefined reference to `__imp_glewGetErrorString'
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:125: undefined reference to `__imp_glewGetString'
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:127: undefined reference to `__imp_glewIsSupported'
  CMakeFiles\Projet_AIN.dir/objects.a(main.cpp.obj): In function `InitializeGlutCallbacks':
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:141: undefined reference to `__imp_glutDisplayFunc'
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:148: undefined reference to `__imp_glutKeyboardFunc'
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:154: undefined reference to `__imp_glutReshapeFunc'
  CMakeFiles\Projet_AIN.dir/objects.a(main.cpp.obj): In function `main':
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:167: undefined reference to `__imp_glutInitDisplayMode'
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:169: undefined reference to `__imp_glutInitWindowPosition'
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:170: undefined reference to `__imp_glutInitWindowSize'
  C:/Users/Thibaut/Documents/Projet_Raffin/src/main.cpp:182: undefined reference to `__imp_glutMainLoop'
  collect2.exe: error: ld returned 1 exit status
  mingw32-make.exe[2]: *** [CMakeFiles\Projet_AIN.dir\build.make:97: bin/Debug/Projet_AIN.exe] Error 1
  mingw32-make.exe[1]: *** [CMakeFiles\Makefile2:67: CMakeFiles/Projet_AIN.dir/all] Error 2
  mingw32-make.exe: *** [Makefile:83: all] Error 2
  14:26:42: Le processus "C:\cmake\bin\cmake.exe" s'est terminé avec le code 2.
  Erreur lors de la compilation/déploiement du projet Projet_AIN (kit : Kat)
  When executing step "Make"
  </code></pre>