Problem
Under Mac OS X if you try to run the core and get the following error:
dyld: Library not loaded: libmysqlclient.18.dylib
Referenced from: /your/path/to/bin/./worldserver
Reason: image not found
Trace/BPT trap: 5
This means it is looking for libmysqlclient.18.dylib file under /usr/lib/ folder but that file is not there.
Solution
The solution is to locate that file and create a symbolic link under /usr/lib/ by typing:
sudo ln -s /path/to/your/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib
For example:
sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib