Documentation build errors from Doxygen when dot missing
When building the documentation via
make doc, it's necessary to have Doxgen installed as well as the
dot tool from Graphviz to generate class hierarchy graphs that are added to the class documentation pages.
dot is not present, the configuration process succeeds but a large number of errors are generated when the documentation build process attempts to call
dot many times to generate the graphs and fails because the command is missing.
The build still ultimately completes but it would be good to remove these errors.
From discussion with @dmoxey, a couple of options seem to be available here:
dota requirement and make the configuration fail if it's missing
dotoptional but update the
Doxyfile.infile to set
NOwhen it is not found which prevents the documentation build attempting to run dot to create the class graphs.
The aim is to go with option (2).