Maxima won't pull out a constant from a linear function

Hello,

I declare "f" to be a *linear function* and "c" to be a *constant*:

declare(f, linear, c, constant);

Now, Maxima correctly does the following simplifications:

f(c * x) = c * f(x)
f(x / 5) = f(x) / 5

However, it won't pull out the constant in the following case:

f(x / c)

This should be f(x) / c,
just like f(x / 5) becomes f(x) / 5.

Do you have any idea how I can make Maxima pull out the constant?
Ideally, it would pull out *any* constant expression, not just a simple 
constant, for example:

f(x / log(42 * %pi)) should become f(x) / log(42 * %pi) ...

Help is greatly appreciated.

Kind regards,
David Scherfgen