lmdb: drops support for non-POSIX.
lmdb: drops support for non-POSIX.

This is 2/9 for https://github.com/ReOpen/ReOpenLDAP/issues/1
and https://github.com/ReOpen/ReOpenLDAP/issues/2

Change-Id: I7ab3d5416381c9477edba4ce9db2f3fdc58a2d3d

leo-yuriev/libfpta,leo-yuriev/libfpta