'make' fails with the following:
[...]
dot -Tpng -Tpng -Gratio=.9 -Gnodesep=.005 -Granksep=.00005
-Nfontsize=9
-Nheight=.1 -Nwidth=.1 < "doc/images/bootstrap-graph.dot" >
"doc/images/bootstrap-graph.png.tmp"
/bin/bash: dot: command not found
make[2]: *** [doc/images/bootstrap-graph.png] Error 127
The idea is that the images produces by dot are part of the tarball, so
Graphviz doesn’t need to be listed as a requirement.
That said, it would be good to mention it in the “Building from Git”
section that you’re working on.