Are dependency lists statically defined?

[John Calcote]

Hi all,

Over the last couple of months, I've seen a number of people asking
questions "around" the topic of building dependency lists. I say
"around" because often the question isn't directly related to a
particular file list such as:

include_HEADERS = file1.h file2.h ... fileN.h

But very often, these lists will contain shell expansions, like this:

if ENABLED_ADDED_FUNCTIONALITY_A
  added_functionality_a = fileX.h fileY.h
endif

include_HEADERS = file1.h file2.h $(added_functionality_a) ... fileN.h

Now, here's my question: I've always been under the impression that
such dependency lists MUST be statically defined for the sake of
automake. Is this no longer true? Or was it ever true?

If it's not true, then what is the recommended method for building
more dynamic dependency lists?

Thanks,
John