Handover, Make

First, congratulations Junio, on taking over this stuff, and all the best.

Second, the killer argument, in the 'Recursive Make ... harmful' is the basic one that Recursive Makes breaks up the dependancy graph, and almost guarentees that it is wrong unless you do a lot of work to fix that artifact. Now git is small enough that make clean; make won't take too long but git is also a basis for other layers, so there is good reason to try to get it right.