... by making a lot of objects unsigned, and some signed.
casts which lose precision and change the sign in one go (ssize_t and
time_t to uint on LP64) are made explicit as well.
the combinations of the various options made quite a mess. additionally,
'RequireSSL no' is inherently insecure - "use SSL if available" is plain
stupid.
the old options are still accepted, but will elicit a warning.
