title: Trying to build OpenCV 2.4.1 with OpenGL support
body: <p>I am trying to build OpenCV 2.4.1 with OpenGL support, and it keeps faling. I have OpenGL installed in my Ubuntu 11.04, libs are under /usr/lib/libGL.so as usual. I know my OpenGL installation is correct because I have C++ OpenGL projects that compile, link and run OK.</p>
  
  <p>I run the cmake command as follows, because I want both CUDA and OpenGL support. </p>
  
  <pre><code>/data/OpenCV-2.4.1/build $ cmake -D WITH_OPENGL=ON -D CMAKE_BUILD_TYPE=RELEASE -D WITH_CUDA=ON -D CUDA_TOOLKIT_ROOT_DIR=/usr/local/cuda/ -D BUILD_EXAMPLES=ON -D WITH_TBB=ON ..
  </code></pre>
  
  <p>This is the output I get from this, telling me CUDA was properly detected, but OpenGL wasn't</p>
  
  <pre><code>-- General configuration for OpenCV 2.4.1 =====================================
  -- 
  --   Platform:
  --     Host:                        Linux 2.6.35-32-generic x86_64
  --     CMake:                       2.8.8
  --     CMake generator:             Unix Makefiles
  --     CMake build tool:            /usr/bin/make
  --     Configuration:               RELEASE
  -- 
  --   C/C++:
  --     Built as dynamic libs?:      YES
  --     C++ Compiler:                /usr/bin/c++ (ver 4.4.4)
  --     C++ flags (Release):         -Wall -Wno-long-long -pthread -fomit-frame-pointer -msse -msse2 -ffunction-sections -O3 -DNDEBUG   -DNDEBUG
  --     C++ flags (Debug):           -Wall -Wno-long-long -pthread -fomit-frame-pointer -msse -msse2 -ffunction-sections -g  -O0 -DDEBUG -D_DEBUG -ggdb3
  --     C Compiler:                  /usr/bin/gcc
  --     C flags (Release):           -Wall -Wno-long-long -pthread -fomit-frame-pointer -msse -msse2 -ffunction-sections -O3 -DNDEBUG  -DNDEBUG
  --     C flags (Debug):             -Wall -Wno-long-long -pthread -fomit-frame-pointer -msse -msse2 -ffunction-sections -g  -O0 -DDEBUG -D_DEBUG -ggdb3
  --     Linker flags (Release):      
  --     Linker flags (Debug):        
  -- 
  --   OpenCV modules:
  --     To be built:                 calib3d contrib core features2d flann gpu highgui imgproc legacy ml nonfree objdetect photo python stitching ts video videostab
  --     Disabled:                    -
  --     Disabled by dependency:      -
  --     Unavailable:                 androidcamera java
  -- 
  --   GUI: 
  --     QT 4.x:                      NO
  --     GTK+ 2.x:                    YES (ver 2.22.0)
  --     GThread :                    YES (ver 2.26.1)
  --     GtkGlExt:                    NO
  --     OpenGL support:              NO
  -- 
  --   Media I/O: 
  --     ZLib:                        /usr/lib64/libz.so (ver 1.2.3.4)
  --     JPEG:                        /usr/lib64/libjpeg.so (ver 62)
  --     PNG:                         /usr/lib64/libpng.so (ver 1.2.44)
  --     TIFF:                        /usr/lib64/libtiff.so (ver 42 - 3.9.4)
  --     JPEG 2000:                   /usr/lib64/libjasper.so (ver 1.900.1)
  --     OpenEXR:                     /usr/lib64/libImath.so /usr/lib64/libIlmImf.so /usr/lib64/libIex.so /usr/lib64/libHalf.so /usr/lib64/libIlmThread.so (ver 1.6.1)
  -- 
  --   Video I/O:
  --     DC1394 1.x:                  NO
  --     DC1394 2.x:                  NO
  --     FFMPEG:                      YES
  --       codec:                     YES (ver 54.23.100)
  --       format:                    YES (ver 54.6.100)
  --       util:                      YES (ver 51.54.100)
  --       swscale:                   YES (ver 2.1.100)
  --       gentoo-style:              YES
  --     GStreamer:                   
  --       base:                      YES (ver 0.10.30)
  --       app:                       YES (ver 0.10.30)
  --       video:                     YES (ver 0.10.30)
  --     OpenNI:                      NO
  --     OpenNI PrimeSensor Modules:  NO
  --     PvAPI:                       NO
  --     UniCap:                      NO
  --     UniCap ucil:                 NO
  --     V4L/V4L2:                    Using libv4l (ver 0.8.8)
  --     Xine:                        NO
  -- 
  --   Other third-party libraries:
  --     Use IPP:                     NO
  --     Use TBB:                     YES (ver 3.0 interface 5000)
  --     Use Cuda:                    YES (ver 4.2)
  --     Use Eigen:                   YES (ver 2.0.15)
  -- 
  --   NVIDIA CUDA:                   (ver 4.2)
  --     Use CUFFT:                   YES
  --     Use CUBLAS:                  NO
  --     NVIDIA GPU arch:             11 12 13 20 21 30
  --     NVIDIA PTX archs:            11 12 13 20 21 30
  --     NVIDIA GPU features:         11 12 13 20 20 30 20
  -- 
  --   Python:
  --     Interpreter:                 /usr/bin/python (ver 2.6.6)
  --     Libraries:                   /usr/lib64/libpython2.6.so (ver 2.6.6)
  --     numpy:                       /usr/local/lib/python2.6/dist-packages/numpy/core/include (ver 2.0.0.dev-27befc8)
  --     packages path:               lib/python2.6/dist-packages
  -- 
  --   Documentation:
  --     Build Documentation:         NO
  --     Sphinx:                      NO
  --     PdfLaTeX compiler:           /usr/local/texlive/2011/bin/x86_64-linux/pdflatex
  -- 
  --   Tests and samples:
  --     Tests:                       YES
  --     Performance tests:           YES
  --     Examples:                    YES
  -- 
  --   Install path:                  /usr/local
  -- 
  --   cvconfig.h is in:              /data/OpenCV-2.4.1/build
  -- -----------------------------------------------------------------
  -- 
  -- Configuring done
  -- Generating done
  -- Build files have been written to: /data/OpenCV-2.4.1/build
  </code></pre>
  
  <p>Any guess what is missing?</p>