!!! existing preserved libs:
>>> package: dev-db/mysql-5.5.38
 *  - /usr/lib64/libmysqlclient.so.18
 *  - /usr/lib64/libmysqlclient.so.18.0.0
 *      used by /usr/lib64/libmysqlcppconn.so.6.1.1.1 (dev-db/mysql-connector-c++-1.1.1)
 *      used by /usr/lib64/perl5/vendor_perl/5.16.3/x86_64-linux/auto/DBD/mysql/mysql.so (dev-perl/DBD-mysql-4.20.0)
Use emerge @preserved-rebuild to rebuild packages using these libraries