MDB_TOOL mode vs. large mdb_env_set_maxreaders()?

[Hallvard Breien Furuseth <h.b.furuseth@usit.uio.no>]

If an lmdb application configures a non-default maxreaders,
this setting is ignored if a tool like mdb_copy is already
running (maybe from crontab).

I suggest mdb_copy & co should use an MDB_TOOL env flag
which requires the lockfile (if any) to be valid, and only
partly reinitializes it.  The upcoming MDB_ROBUST flag might
also make use of this.  An alternative would be to stuff
this into the metapages, but that seems less flexible.

-- 
Hallvard