MySQL 5.5 has default storage engine InnoDB. In MariaDB 5.5 it's still MyISAM.
I tried the latest kvm-bintar-hardy-x86 5.5-release build from the buildbot archive (build-2043).
- unpack the build,
- start server with --no-defaults,
- connect to the server,
- SELECT @@storage_engine or SHOW ENGINES
=> see that MyISAM is default.