Enable building of legacystore and linearstore
Add libaio-dev and libdb5.1++-dev as Build-Depends
Disable the legacy store.
Forcibly disable the legacy store.
Be explicit about where to find BerkeleyDB
Specify full path to libdb_cxx
Tidy up configure rule.
Use DB_CXX_INCLUDE_DIR, not (the undefined) DB_INCLUDE_DIR
Update rules to specify the full path to libdb_cxx.so