I disagree with the characterization that this is "not very hard" (and my initial assessment was "questionable incantations" which I think is also accurate):

https://www.gnu.org/software/automake/manual/html_node/Multi...

Definitely not handled "simple and well" as posited by the OP.

the horrible contortions listed on the linked page are required for the pathological "some of the targets that are built together got deleted, but the primary one did not" case, which in my experience Does Not Happen (or when it does, it is a symptom of deeply suspect practices -- like shitting where you ea^W^W^W^Wkeeping build artifacts and sources in the same directory, or relying on manually deleting artifacts to force a rebuild instead of getting the bloody dependencies right in the first place, etc.)

(I guess what I'm trying to say here is that the 80% solution is not nearly as hard as that linked page makes it seem).