Well, I don't think libmysqlclient.18.dylib exists on my system. Mac OS X doesn't have a "ldd" command; people seem to use otool for this. Not sure this is what we're looking for, but here's some info :-)

/-> otool -L /opt/local/lib/mysql5/mysql/libmysqlclient.16.dylib
/opt/local/lib/mysql5/mysql/libmysqlclient.16.dylib:
    /opt/local/lib/mysql5/mysql/libmysqlclient.16.dylib (compatibility
+ version 17.0.0, current version 17.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current v
+ersion 159.1.0)
    /opt/local/lib/libssl.1.0.0.dylib (compatibility version 1.0.0, cu
+rrent version 1.0.0)
    /opt/local/lib/libcrypto.1.0.0.dylib (compatibility version 1.0.0,
+ current version 1.0.0)
    /opt/local/lib/libz.1.dylib (compatibility version 1.0.0, current 
+version 1.2.5)
[download]

The fix described at MySQL bugs involves using install_name_tool -id but it's not clear to me what to use for arguments, or where to put this command (.bashrsc?)

Thx.