The openldap-2.3.37.ebuild has an elog message about a sample bdb config file in /usr/share/doc/${PF}/DB_CONFIG.fast.example.gz but on my system ecompress uses bzip2 not gzip, so the file is in fact DB_CONFIG.fast.example.bz2. You should probably replace ".gz" with the output from "ecompress --suffix".
*** This bug has been marked as a duplicate of bug 169772 ***