Request: Print actual number of pages after compiling

[Christopher Heckman]

This isn't so much a bug as an annoyance.

Frequently when I'm typesetting music, I'm trying to resize the output
to fit on the minimum number of pages (while remaining readable, of
course). When Lilypond is compiling, one of its messages is "Fitting
music on 1 or 2 pages..." Obviously, in this situation, I want to know
the exact number of pages without re-opening the .pdf file. Could
someone add a one-line statement to print out the actual number of
pages, near the "Success: compilation successfully completed" message?

--- Christopher Heckman