With dev-db/mariadb-10.2.8 (not tested with version 10.2.7-r2) both freeradius-3.0.14 and freeradius-3.0.15 fail to compile with error "fatal error: mysql_version.h: No such file or directory".
I think it was in /usr/include/mysql, but now it can be found in /usr/include/server/mysql now - for whatever reason I don't know. At least this seems to be the case with asterisk. It may be also just like that in this case...
Tested against 10.2.15 and 10.3.7 of mariadb. Freeradius 3.0.15 built against both with no issue.
please retest with 3.0.17