back-bdb indexing

["Howard Chu" <hyc@highlandsun.com>]

I've just committed a bunch of bugfixes to back-bdb and turned on #define
BDB_FILTER_INDICES. With some simple indexed searches it appears to work. I
haven't tried adds/deletes/modifications to any of the indices yet. Please
give it a try...

Note that creating an index after the fact is extremely slow. (In fact, any
write operation is extremely slow.) I suggest you build the database and
index in one operation (ldapadd or slapadd) rather than just building the
database and then running slapindex later.

  -- Howard Chu
  Chief Architect, Symas Corp.       Director, Highland Sun
  http://www.symas.com               http://highlandsun.com/hyc
  Symas: Premier OpenSource Development and Support