C program structure -- generate a tree diagram?

[Robert Raisch]

Is there a PD source for generating a tree diagram of the calls used in
a application written in 'C'? 

What I'm thinking of is a program that, when given a group of source files,
produces a tree of who calls who, starting at main().

I have a rather large system, running under MSDOS (Gack.) that I need to
extract only the bits that do the work, and Microsoft C seems to want to
*always* link in ALL the modules I tell it to, regardless of whether or
not the code is actually used.  <heavy sigh>  Makes for an enormous 
executable, even when I *know* I'm only using a small portion of the code.

The program that you recommend should run under SUNOS 4.1.

Thanks ever so much.  -RR

-- 
"I ate his liver with some fava beans and a nice chianti." -Lector