Following a discussion on dspam-users mailing list, dpsam ships now with
two .sql for creating the mysql tables:
mysql_objects.sql.space.optimized and mysql_objects.sql.speed.optimized
As a note, I doubt that there is much "space" optimization with the
respective table structure, due to the stored data pattern. The current
Makefile doesn't install them and tries to remove mysql_objects.sql on
deinstall; the pkg-plist doesn't include them.
Included Makefile.diff and pkg-plist.diff should fix that.[1]

If compiled with trusted user security (default), dspam doesn't pass the
destination recipient to the LDA (the last word from the
untrusted.mailer_args); included patch-dpsam.c fixes that. [2]

IMHO OPTIONS are there to be used, so I've also added some;
feel free to drop them, if you want (for installing only the little fix in Makefile.diff
post-patch:
@@ -91,7 +137,7 @@ is enough). [3]

Bumped PORTREVISON in the patch.

[1] Env: postfix-2.0.19, mail.local as LDA, -r-s--x--x on dpsam binary;
if someone finds a way to run dspam from postfix/local without o=x,
please let me know.

How-To-Repeat: 

[1] Obvious (make extract and see work/dspam/tools.mysql_drv).

[2] Compile dspam --with-trusted-users-security (default), use mail.local as 
LDA (default), don't put something after therecipient in untrusted.mailer_args

[3] -