If you don't know what these are you probably don't need them.
The flex port is a version I did years ago for my own use, and have recently recompiled to be 32 bit compatible. I'm obliged to say: "This product includes software developed by the University of California, Berkeley and its contributors" - see the source code (provided) for the full licence terms.
The verson of bison here is a quick and nasty hack to get it working on 32 bit systems. It's based on previous ports by Martin Carradus and Tom Hughes. It's released under the GPL, again full conditions are included in the distribution.
Download GNU bison version 1.24
Both need the latest !System updates from Castle Technology. You can find Castle's downloads page here.