lisp dependencies

[raek@athena.mit.edu (Robyn A E Kozierok)]

Does anyone know where I could find a lisp utility that would take a bunch
of lisp files and work out a dependencies graph for them (i.e. which files
use functions or variables defined in which other files)

I realize that in some cases this can be very difficult to impossible
(if symbol names are generated by macros, for example) but would be 
satisfied with something that handles just the "simple" cases.

I am using MCL in case that matters.

Thanks,
--Robyn