While that code was apparently always intended to be there it did not run. Running it causes compilation to fail with errors like
cctki_Cactus.h not found if eg one uses an empty thorn list:
make null-config THORNLIST=/dev/null PROMPT=no
Pull request https://bitbucket.org/cactuscode/cactus/pull-requests/118/cactus-handle-including-cactus corrects this by only including the file if indeed it was created. This is in line with how capabilities of “real” thorns are handled.