Gtk/C code development tools

[Steven Boyls <sboyls tuckerenergy com>]

I'd like to get an idea on what development processes and tools tools 
people are using
for their Gtk/C applications.  My previous experience was object 
oriented and included C++/Java/C#.
We used a number to different development processes such as RUP and 
others.  I now work in a small
group and we write straight C code and the GTk on Linux. I'd like to try 
to find some modeling tools that work
well in this type of environment. Most of the products that are on the 
market work well for OO development.
I'm not looking for an IDE, I'm looking for a way to document our 
designs, GUIs, data flow, etc.

Any thoughts or recommendations?

Steve