The former module is a Makefile parser which parses Makefiles to simple ASTs while the latter is a GraphViz application that generates pretty graphs that depicts the building flow directly from Makefiles. The pictures produced by GraphViz are amazingly good. I don't think I'm able to produce better pictures manually with MS Visio. Furthermore, everything in the output pictures are fully parameterized, leading to good flexibility.
Nadim Khemir told me that he was looking forward to use Makefile::Parser in his PerlBuildSystem, which urges me to improve this stuff actively.
More feedbacks are most welcomed. Thank you in advance.