Assertion failed: check for file existence

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I already follow the MAVROS install tutorial in there:

https://dev.px4.io/en/ros/mavros_inst...

When I type command $catkin build ,

I get cmake error like follow:

Errors <<   image_transport_tutorial:cmake /home/paris/catkin_ws/logs/image_transport_tutorial/build.cmake.log
CMake Error at /opt/ros/kinetic/share/catkin/cmake/assert.cmake:17 (message):
Assertion failed: check for file existence, but filename
(RT_LIBRARY-NOTFOUND) unset.  Message: RT Library

Call stack(most recent call first):
    /opt/ros/kinetic/share/catkin/cmake/tools/rt.cmake:42 (assert_file_exists)
    /opt/ros/kinetic/share/catkin/cmake/old.cmake :147(include)
    /opt/ros/kinetic/share/catkin/cmake/catkinConfig.cmake :20(include)
    Cmakelists.txt: 4 (find_package)

Before, if the code in src file don't include the image_transport related libraries, I can run $catkin build without any error.

Wonder that what will cause this problem because I can't find any solution in the internet.Tks for help!