Build opencv_contrib sample executables on Linux

edit

System: VM Ubuntu 14.04 x64

Summary:
I'm building OpenCV 3.0.0-dev with the contrib modules from https://github.com/Itseez/opencv_contrib but I can't get the executables from opencv_contrib.

I was trying to follow this tutorial about the tracking API: http://docs.opencv.org/trunk/modules/tracking/doc/tracking.html

Somewhere it says: To see how API works, try tracker demo: https://github.com/lenlen/opencv/blob/tracking_api/samples/cpp/tracker.cpp

But that's a forked old repository (by user lenlen), not the official repository. In the recent versions (with the new repos) it seems like that file is not in that location anymore but in: https://github.com/Itseez/opencv_contrib/blob/master/modules/tracking/samples/tracker.cpp

The problem: I'm being able to build OpenCV without errors, but I can't see how to build that executable file from opencv_contrib, or where is it getting located.

I've tried:

• Setting up OPENCV_EXTRA_MODULES_PATH with: cmake -D OPENCV_EXTRA_MODULES_PATH=../opencv_contrib/modules ..
• Setting up INSTALL_C_EXAMPLES with: cmake -D INSTALL_C_EXAMPLES=ON ..
• Entering in opencv_contrib, creating and entering into a "build" directory and from there executing: "cmake .." ...but that gives errors (no CMakeLists.txt).
• Entering in "opencv_contrib/modules/tracking/", creating and entering into a "build" directory and executing "cmake .." (because there's a CMakeLists.txt inside of the tracking directory). But that also gives errors.
• Entering in "opencv_contrib/modules/tracking/samples/" and executing "g++ tracker.cpp", but that also gives errors.

Thanks in advance!