Vasil,
Passing the variable to the cmake (cmake -DCMAKE_FIND_ROOT_PATH=/usr ../) helped.
Solution with modification PATH such that /usr is at the beginning also did the job. Thank you very much.
Do you know how to explain that problem? At the Ettus website it is said that CMake is looking for the filesystem items using the wrong location (/bin) which causes wrong calculation of the root path for different directories needed by the build process.
Is there a simpler explanation for a beginner like me?
Thanks in advance,