sphinx-build not found

[Russell L. Carter]

Greetings,

Quite a few ports are now being skipped by the not unheard of
problem with "sphinx-build not found".  Including llvm6 and 7.
I've checked UPDATING and google, but no hints, other than this
problem has happened in the past.

Is there something I can do or should I just be patient?  NBD
if I need to be patient.

Thanks,
Russell