Recursive `Make` and `-J`

What happened

Today I looked into “recursive” invocations of make; that is, cases in which a Makefile recipe itself invokes make. The official documentation is quite good, but since I’m working with a range of different GNU Make versions, I looked at how the behavior has changed over time, from GNU Make 3.81 to 4.3.

Summary assembled by rule from the sources below

Sources