Just a quick FYI for those attempting to build libzdb 2.10.5 on OS X (10.8) Mountain Lion. Libzdb failed to build on 10.8 because Apple had removed libfl which was required to build a scanner tool used by libzdb.
Thanks to a patch from Johan Bergström, I have uploaded a new version of libzdb 2.10.5 which modify configure to also check for libl which works equally well for libzdb. There are no other changes other than configure.ac so I decided to keep the version number. (Apologies to package purists which may not like this).
So if you have updated to Mountain Lion, please download libzdb _again_ from http://tildeslash.com/libzdb/dist/libzdb-2.10.5.tar.gz and it should work again.