Find all CMake targets declared in a directory (recursively)

CMakeLists.txt

function(print_all_targets DIR)
    get_property(TGTS DIRECTORY "${DIR}" PROPERTY BUILDSYSTEM_TARGETS)
    foreach(TGT IN LISTS TGTS)
        message(STATUS "Target: ${TGT}")
        # TODO: Do something about it
    endforeach()

    get_property(SUBDIRS DIRECTORY "${DIR}" PROPERTY SUBDIRECTORIES)
    foreach(SUBDIR IN LISTS SUBDIRS)
        print_all_targets("${SUBDIR}")
    endforeach()
endfunction()

print_all_targets(.)