# Adds a submodule subdirectory to be included in cmake. Will automatically
# init it if its empty, and can optionally checkout any tag/branch if specified.
macro(ksutil_add_submodule_directory PATH)
    set(oneValueArgs TAG RENAME)

    cmake_parse_arguments(OPTS "${options}" "${oneValueArgs}" "" ${ARGN})

    # See if the dir is empty or not
    file(GLOB RESULT ${PATH}/*)
    list(LENGTH RESULT RES_LEN)
    if(RES_LEN EQUAL 0)
        # Empty so update it
        execute_process(COMMAND git submodule update --init ${PATH} WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR} RESULT_VARIABLE CLONE_RESULT)
        message("Clone result: ${CLONE_RESULT}")
    endif()

    # And check out the right tag
    if (OPTS_TAG)
        execute_process(COMMAND git checkout ${OPTS_TAG} RESULT_VARIABLE CHECKOUT_RESULT)
        message("Checkout result: ${CHECKOUT_RESULT}")
    endif()

endmacro()