ClamAV

Building / Upgrading

Download the recent ClamAV source to src/apps/milters
Set your environment variables based on our standard building rules
Look at previous version's config.log, and run the same configure line on the new version (unless there's something new you wish to enable, etc.)
Build it.
Disable cron on the build machine (usually one of the mx servers)
make-install it.
Stop/Start clamd via /etc/init.d/clamd and make sure the new version works.
Copy bins, sbins & libs from /etc/mail/<dir> to cfengine/files/mail/mx/software/@sys/... as appropriate. You can also gmake-install prefix= there, if you'd like.
release admin.cfengine
turn cron back on
profit.