|sys-libs/db support needed to migrate old (pre-3.13 evolution versions) addressbook data
|Enable sys-libs/db database backend for header caching
|Enable BDB (Berkley DB) backend for header caching
|Support legacy wallets in Berkeley DB format
|build programs that use berkdb (just arpd)
|enable compatibility layer for UNIX-like dbm and ndbm interfaces
|Build the pam_userdb module, that allows to authenticate users against a Berkeley DB file. Please note that enabling this USE flag will create a PAM module that links to the Berkeley DB (as provided by sys-libs/db) installed in /usr/lib and will thus not work for boot-critical services authentication.