Ask HN: Tool to Visualize C Project?

I’m trying to port an old C project to a new platform. There are a lot of subdirectories, with files that then include headers in other directories.

I want to start porting directory by directory, keeping the project buildable at each step.

I figured that topologically sorting the dependency graph (based on headers) is a good start, but I don’t know of any tools that can build the graph automatically.

A simple graph of header includes should suffice.

Are there any tools you would recommend for this?