MariaDB-* packages are from external 'x86_64 only' repository. Other
architectures use CentOS packages.
Split needs to be done as 'mariadb-devel' is provided by three different
packages on x86-64.
Partially-Implements: blueprint multiarch-and-arm64-containers
Depends-On: I71ddb7ef57c64d2505cac96724b1ab6772a57d6a
Change-Id: I9f3394eb35723f2bbf3205c6af6101b5a9daed38