cflow on SunOS 3.5

[Al Donaldson]

When I run "cflow mumble.c" on my Sun 3/50 (Sun OS 3.5) it bombs out
with a message "fatal error in cpp: broken pipe", but it works like 
a champ if I feed it .o files.

Since I'm new to cflow, I thought I might be misreading the man page 
(you know, about how it processes C code and all that...), but a friend 
tried it on Ultrix and that version works fine.  

Any ideas?  Is there a public domain cflow?  

Al Donaldson
al at escom.com