This is regarding:
https://mariadb.com/kb/en/mariadb/about-federatedx/

Specifically, the last section bullet

My employer started a project to add a generic ODBC source to the FederatedX plugin.  Once into the project, it was decided that creating a specific source to our COM server would be faster.  The ODBC source did work, but it was buttoned up after read-access was completed.  I'm not sure if it will ever be released, but I thought we should distribute the code regardless.

Please find an incredibly boring page here:
http://stonebond.com/mariadb-contributions/

Included in the zip are the changes to source files, as well as two additional files for connecting to ODBC and to our COM dll.  These were only compiled on windows, so likely are not ready for inclusion in the source tree.  

Let me know if you have any questions.