Build for the "default" config only, which can be
asyncyfy 0,1, or 2 depending on Qt build configuration.
Change-Id: I29d9a11b30325491151fc4e621272e5390681fa7
Reviewed-by: Jøger Hansegård <joger.hansegard@qt.io>
Reviewed-by: Lorn Potter <lorn.potter@qt.io>