Bisecting with Address Sanitizer and Undefined Behavior Sanitizer
indicates this was fixed upstream in commit
fed9dd288d1e29e0ca0b1c9e2f800e91d5c78f4d
(https://gitlab.com/graphviz/graphviz/-/commit/fed9dd288d1e29e0ca0b1c9e2f800e91d5c78f4d),
so this bug was filed upstream as
https://gitlab.com/graphviz/graphviz/-/issues/1225. The fix landed in
Graphviz 2.42.0.
