ARDRONE AUTONOMY - Build and add external projects

edit

Hello, I want to create a patch for the ardroneLib of autonomy lab. The CMakeLists includes an external project:

include(ExternalProject)
ExternalProject_Add(ardronelib
    GIT_REPOSITORY git://github.com/AutonomyLab/ardronelib.git
    GIT_TAG 2f987029c55531e4c0119c3600f9c57f935851ed
    PREFIX ${CATKIN_DEVEL_PREFIX}
    CONFIGURE_COMMAND echo "No configure"
    BUILD_COMMAND make
    INSTALL_COMMAND make install INSTALL_PREFIX=${CATKIN_DEVEL_PREFIX}/lib/
    BUILD_IN_SOURCE 1
)

I wont to use this projectfiles locally. So I copied it in the sourcefolder:

catkin_ws/src/my_project/
                         ardronelib/
                         src/ ...
                         launch/ ...
...

the ardronelib folder contains the makefile of the project.

ardronelib/
           ARDroneLib
           .git
           .travis.yml
           LICENSE
           Makefile
           README.md

How can I build an include this library locally? My approach with:

include(ExternalProject)
ExternalProject_Add(ardronelib
    SOURCE_DIR=${PROJECT_SOURCE_DIR}/ardronelib
    PREFIX ${CATKIN_DEVEL_PREFIX}
    CONFIGURE_COMMAND echo "No configure"
    BUILD_COMMAND make
    INSTALL_COMMAND make install INSTALL_PREFIX=${CATKIN_DEVEL_PREFIX}/lib/
    BUILD_IN_SOURCE 1
)

and several others didn't work. Any ideas how to build the project so that later I can use "ardronelib" within my project? I am a bit desperate so thanks a lot for your help!