ANAME_DB re-enable with patch.

[Greg Hudson]

On Wed, 2010-09-01 at 16:54 -0400, Russ Allbery wrote:
> Have folks considered embedding TDB?  http://tdb.samba.org/

Embedding (i.e. including the library code in our source tree for) TDB
doesn't seem like it would be very useful unless we also provided a
management tool for aname-to-lname databases, or installed tdbtool.  I'm
not wild about either of those options.

I'm opposed to making additional use of the BDB fork used by the db2
back end.

I'd be okay with a build option to add TDB support (linking against a
system libtdb) via a "TDB:" syntax in auth_to_local.  Because TDB is
part of Samba, I don't think it's unusual for it to appear in a modern
OS.