sharing DB_ENV between DB berkeleydb instances

[Caolán McNamara]

Digging into our memory usage, I see that we have 6 berkeleydb DBs, all
of which are opened with a NULL DB_ENV argument which makes berkeleydb
create an internal one for each, which adds up to a substantial chunk of memory.

On the face of it at least it seems to be legal to share a single DB_ENV among the lot,
i.e. like so...
http://cgit.freedesktop.org/libreoffice/core/commit/?id=76876513479522b37c9047a418521624e27afff6

Anyone know if this is a really bad idea :-)

C.