This is a simple database API. It was inspired by the realisation that
in Samba we have several ad-hoc bits of code that essentially
implement small databases for sharing structures between parts of
Samba. As I was about to add another I realised that a generic
database module was called for to replace all the ad-hoc bits.

I based the interface on gdbm. I couldn't use gdbm as we need to be
able to have multiple writers to the databases at one time.

Compilation
-----------

add HAVE_MMAP=1 to use mmap instead of read/write
add TDB_DEBUG=1 for verbose debug info
add NOLOCK=1 to disable locking code

Testing
-------

Compile tdbtest.c and link with gdbm for testing. tdbtest will perform
identical operations via tdb and gdbm then make sure the result is the
same

Also included is tdbtool, which allows simple database manipulation
on the commandline.

tdbtest and tdbtool are not built as part of Samba, but are included
for completeness.

Interface
---------

The interface is very similar to gdbm except for the following:

- different open interface. The tdb_open call is more similar to a
  traditional open()
- no tdbm_reorganise() function
- no tdbm_sync() function. No operations are cached in the library anyway
- added a tdb_traverse() function for traversing the whole database