This script parses .include and other interesting lines in BSD makefiles
and outputs the result as a GraphViz .dot graph. This allows us to find,
e.g., where in the make system we have defined both CC and LOCALBASE
or both CTFCONVERT_CMD and custom suffix rules.
- Generalize the metadata we can look for.
- Don't output None attributes.
- Normalize paths.
- Give re-definitions a different shape from definitions.
- Add more filename sanitizing.
- Add flags to filter singletons and unconnected components.
- Print the total number of files being parsed.