include(FetchContent) message(STATUS "Fetching json...") FetchContent_Declare( json GIT_REPOSITORY https://github.com/nlohmann/json GIT_TAG v3.11.3 ) FetchContent_GetProperties(json) if(NOT json_POPULATED) FetchContent_Populate(json) add_subdirectory(${json_SOURCE_DIR} ${json_BINARY_DIR} EXCLUDE_FROM_ALL) endif() FetchContent_MakeAvailable(json) message(STATUS "json fetched and is now ready.") set(JSON_FOUND TRUE)