set(genexvar $) if (HAVE_FINAL) set(expected_result 1) else() set(expected_result 0) endif() add_custom_command(OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/copied_file${expected_result}.cpp" COMMAND "${CMAKE_COMMAND}" -E copy "${CMAKE_CURRENT_SOURCE_DIR}/empty.cpp" "${CMAKE_CURRENT_BINARY_DIR}/copied_file${genexvar}.cpp" ) add_library(empty "${CMAKE_CURRENT_BINARY_DIR}/copied_file${expected_result}.cpp") if (HAVE_FINAL) target_compile_features(empty PRIVATE cxx_final) endif()