The find_file command on line 32 in cmake-tool/base.cmake searches explicitly for a directory named "kernel" and the result is stored in KERNEL_PATH. Renaming the kernel directory as stated in Incorporating into your project and defining KERNEL_PATH with the -D option will result in a bogus value for KERNEL_PATH resulting in cmake failing on line 40 (add_subdirectory). Also, the add_subdirectory command itself forces a fixed binary directory named "kernel", which seems unnecessary.