bug#51132: [External] : bug#51132: Make sure user is doubly aware of finished complilations

[Drew Adams]

> > A message is issued, and I think that's sufficient.  Closing.
> 
> Note that you can customize compilation-finish-functions to do all
> sorts of things; you can e.g. send a desktop notification:

Fine.  But by default Emacs should generally pair
notification of starting/continuing progress with
notification of finishing - in the _same manner_,
at a minimum.