On 27/07/2015 jan i wrote:
I totally agree that we cannot include a single bit of Qt code in our source release, but it is legal to reference e.g. include files in the optional source code.
Correct. And of course if you want to bind to a specific version of QT you can add a download link for it and hard-code a MD5 (or similar) hash check. In general you don't want to host the QT tarball on ASF infrastructure for license clarity, but you can use Apache Extras (now in the process of being moved from Google Code to SourceForge) to that aim.
Regards, Andrea.