Add /opt/local/include/db48 only if it exists.
Add /opt/local/include/db48 only if it exists.

(cherry picked from commit 4c69ebed44789be056a7b713bed43e5d3b3a5542)

reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin