I was actually contemplating this last night while looking at another FLOSS project.
I think the specific question you cite should be off-topic - there are other sites where it could be asked and answered. Indeed, a number of projects direct users to StackOverflow as their support forum.
However, SO seems to be (understandably) reluctant to become support central:
If we were to find ourselves struggling to stay relevant or active, I think there might be some value in offering our site as a central support forum for FLOSS projects. It would show support for the community, and almost certainly attract a high volume of traffic.
However, I also suspect it would be difficult to draw the line between support questions, and 'How do I use this function?' type questions.
The support posts would also quickly dwarf the number of questions related to our initial goals.
Perhaps, if no other site wants to take on that role, it might be a candidate for a new Area 51 proposal.