Right, I don't believe you need a FLOSS exception. The ASF's license is compatible with MySQL's thoughts on what the GPL is compatible with. Namely the interface can exist and there are no issues with it being made available. Its the last mile that is at question. If someone compiles the apr and links it against a closed source application then they will need to compile the APR with all GPL code disabled, otherwise if its in an open source environment (or in a web environment where no code is being distributed) they are ok.
The APR question is closely related to how things are "allowed" within PHP. For example, I can build PHP --with-mysql and then bundle PHP with my application which is closed-source and all is OK. The reasoning is that PHP w/o MySQL DB support would be a severe handicap to PHP's usefulness as well as MySQL's potential audience.
Not having a similar allowance for APR would prevent external companies who bundle/provide/distribute Apache2 from having apr-dbd be "MySQL" aware. Considering the pervasiveness of MySQL, this would almost make apr-dbd worthless in those environments and in those distributions.
So yes, it's true that apr (actually apr-util) with apr-dbd would not bundle any MySQL code (just make use of the public API), we would like external agencies to be able to build apr-util/apr-dbd with MySQL support and distribute the end result without requiring it to be OSS (ala PHP).
