md5 c code

I've attached a bit of c code to do md5 checksums on text.  There's
nothing too original here, this was mostly just ripped from rfc1321,
with some driver code added for PostgreSQL.  Also a Makefile and a test
schema.

Sorry if this isn't the right place to post such a thing.  I had just
noticed a question on the pgsql-sql list about this, so I thought, what
the heck, I'll try to contribute something.

Please note that this code is copyright RSA Data Security, Inc.  What
kind of complications that causes for distribution, I have no idea.  It
says unlimited distribution, so seems o.k. to me, but what do I know. 
The copyright notice is preserved in the code and included in the
README.

This function accepts text as input.  I.E. - pg_md5(text).  Since
postgres.h defines both text and bytea to be the same thing (typedef
struct varlena), does that mean this function should also accept binary
input?

-Ron-
ron.peterson@yellowbank.com