@sergiusens This is not necessarily true, and I don’t see a clear proposal above to make a judgement on it.
Trying to drive this topic to a more concrete change, here is a proposal: what if we allowed the architecture field to be defined like this:
architectures:
- [armhf]
- [amd64, i386]
The behavior of snapcraft when it sees a field like that is to build all the architecture sets it can. Each set will result in a single snap, and the value in snap.yaml will be the set itself (either armhf or amd4, i386 in the case above).
We may also introduce an --arch flag that tells snapcraft to only build the snaps that work on that particular architecture. In the example above, both --arch=i386 and --arch=amd64 would cause snapcraft to only build the second snap, even it knows how to build an arm snap.
How does that sound?