Well, I admit he does have a point. While we haven't given up all hopes to implement real multiproject support one day, most of the people subscribed here did so long time ago and have most likely switched to alternative solutions since.
So we can indeed close this one as "duplicate", and start anew. Funny enough, the description of this ticket while extremely short still mostly captures what I'd like to see as multiproject support…
So I just created #11025 to that effect.
If anyone felt like modifying or commenting further on the present ticket, please use #11025 instead.