new ldb group mapping code

[derrell at samba.org]

tridge at samba.org writes:

> ldb already has a two step connect process. ldb_init() gives you a
> handle...
>
>  >  What is wrong with simply specifying a way to define the mode in
>  > the ldb_connect().
>
> yes, that would be equivalent to tdb_open_ex(). I'm trying to get away
> from that, as it means that whenever you want a new thing that can be
> set, you have to change the API.

I solved this problem in libsmbclient by adding option_set() and option_get()
functions.  Options are set via this interface, which means that new options
can be added without changing the API.  How the options affect the internals
is not exposed to the user.  For ldb, you'd likely do ldb_init() and then
optionally call something like ldb_option_set("open_mode", 0600)

Cheers,

Derrell