> The relationship to Makefile syntax is that a topological sort is
> happening in the background.

Not only that, but the surface syntax has identical layout:

;; Scheme

(let ((d (using c
              (k c)))
         (a (f))
         (c (using b
               (h b)))
         (b (g)))
   <expr>)

## Make

d: c
     k c

a:
     f

c: b
     h b

b:
     g