Dependencies for clean rule

[Erik Rull]

Hi all,

I have several targets that depend on each other.
For cleaning them up, I have to take care that the clean dependencies are just
the other way round.

e.g.

a: b c
b: d e
c:
d:
e:

If I want to make a the dependencies assert that the build order is correct.
If I want to make "clean" e.g. c, I should clean a first.

Is there a way to find the "reverse-order" of the dependencies? Of course, I
could manually write the clean-rule-dependencies, but that would be too easy
(and generate additional errors when the number of targets and dependencies are
bigger).

Maybe someone solved that already, I did not yet find a smooth solution for 
that.

Thanks in advance.

Best regards,

Erik