Found a third public domain md5 implementation:

http://openwall.info/wiki/people/solar/software/public-domain-source-code/md5

while looking a way to remove an openssl or libgnutls-openssl dependency from zoneminder. I'm planning to suggest to upstream that this be bundled to remove the dependency, since we still seem to have no reasonable md5 shared library. Figured we'd want to add this to http://fedoraproject.org/wiki/Packaging:No_Bundled_Libraries as md5-peslyak.

I suspect this is a "just do it" thing, but I figured I'd file a ticket for it first.