R devel - Jul 2007 - [OT] help in setting up a doxygen configuration file

I would appreciate some pointers on how to set up a doxygen
configuration file for C source code.  In particular I would like to
be able to generate a call graph.  I tend to write a lot of short
utility functions and, by the time the final design reveals itself, it
is quite possible that some of these utilities are called in only one
place.  That's not a bad thing to have happen but I would like to know
about it when it does occur.

Doxygen seems to emphasize C++ classes and I can't manage to get it to
do much with my C functions.  The package sources are available at

https://svn.R-project.org/R-packages/branches/gappy-lmer/

The doxygen configuration file is gappy-lmer/inst/doc/Doxyfile

I have written all the Javadoc-style comments in the source files such
as gappy-lmer/src/lmer.c but I can't seem to get doxygen to notice
them.