SlackBuildsOrg/system/makefile2graph

makefile2graph (creates a dependency graph from a Makefile)

Creates a graph of dependencies from GNU make Makefile.

Output is a graphviz dot file, a Gexf-XML file, or a list of the
deepest independent targets that should be made. Sub-Makefiles are not
supported.

Optional dependencies: To actually generate visual graphs, you will
need or or both of:

graphics/graphviz
graphics/graph-easy

Example: If there's a Makefile in the current directory, try this:

  make -Bnd | make2graph | dot -Tpng > graph.png