In my case, I solved by adding a couple of symbolic links as in http://ageekstory.blogspot.com/2011/04/installing-massive-coupon-on-mac-os-10.html
as following:
sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib
sudo ln -s /usr/local/mysql/lib /usr/local/mysql/lib/mysql