Add "MeCab" support to MariaDB

This is something added in MySQL 5.7, so perhaps it should be included in MariaDB.

"ngram and MeCab full-text parser plugins. As of MySQL 5.7.6, MySQL provides a built-in full-text ngram parser plugin that supports Chinese, Japanese, and Korean (CJK), and an installable MeCab full-text parser plugin for Japanese.

For more information, see Section 13.9.8, “ngram Full-Text Parser”, and Section 13.9.9, “MeCab Full-Text Parser Plugin”."

http://dev.mysql.com/doc/refman/5.7/en/mysql-nutshell.html

And the 2 respective links referenced above are:

http://dev.mysql.com/doc/refman/5.7/en/fulltext-search-ngram.html
http://dev.mysql.com/doc/refman/5.7/en/fulltext-search-mecab.html