Hm,
maybe there is some leftover.
I made a clean port for you, please grap it here:
http://sorry.mine.nu/patches/FreeBSD...-stukov.tar.gz
extract the port with the following command
# tar xvfz spamd-stukov.tar.gz -C /usr/ports/mail/
then
# cd /usr/ports/mail/spamd-stukov/
# make
If you have problems send me a PR