Currently, MariaDB's server does not link under FreeBSD's aarch64 architecture due to the use of sbrk, which does not exist under that architecture. MySQL has corrected this issue with the following commit:
I have tested patching all current versions of MariaDB from FreeBSD's ports tree (5.5, 10.0, 10.1 and 10.2) under the aarch64 architecture, patching only mysys/stacktrace.c in all those versions, and it allows MariaDB to link. I have sent a patch to the FreeBSD ports tree here:
If the patch that MySQL utilized was applied to all supported versions of MariaDB, it would allow MariaDB to work on more FreeBSD platforms.