After years of MySQL development happening largely behind closed doors, Oracle has been making real progress towards making the MySQL project more open and community-oriented.
Founder and CEO here. Great question. Right now, since you are linking MySQL files that means that all the extenions need to be GLPv2 or compatible license. In the future, we are hoping to have a stable SDK that is indepedent of the MySQL files so that if you run it out of process, that would give more licensing options to folks. There is a proof of concept of an out-of-process mode for the extensions in the alpha, but we haven't spent much time on proving it out.