diff -ur OpenCV-2.4.2.orig//cmake/OpenCVFindLibsVideo.cmake OpenCV-2.4.2/cmake/OpenCVFindLibsVideo.cmake
--- OpenCV-2.4.2.orig//cmake/OpenCVFindLibsVideo.cmake	2012-07-09 23:47:24.910117311 +0000
+++ OpenCV-2.4.2/cmake/OpenCVFindLibsVideo.cmake	2012-07-09 23:48:25.689181021 +0000
@@ -75,6 +75,7 @@
 ocv_clear_vars(HAVE_LIBV4L HAVE_CAMV4L HAVE_CAMV4L2)
 if(WITH_V4L)
   CHECK_MODULE(libv4l1 HAVE_LIBV4L)
+  CHECK_MODULE(libv4l2 HAVE_LIBV4L2)
   CHECK_INCLUDE_FILE(linux/videodev.h HAVE_CAMV4L)
   CHECK_INCLUDE_FILE(linux/videodev2.h HAVE_CAMV4L2)
 endif(WITH_V4L)