Append to CMAKE_PREFIX_PATH?

I want help CMake find an external library. If I were working just on the bash I would call cmake with:

    CMAKE_PREFIX_PATH=$CMAKE_PREFIX_PATH:$HOME cmake ..

    cmake --build .

and it would just work.

How do I archive the same with CLion, preferably without changing the CMakeLists.txt.

I tried to add this to all of my configurations: