Displaying typesetting information at compile time

[Richard Shann]

I wonder if someone could suggest how to get LilyPond to emit various
bits of information about the score it is typesetting. Specifically can
it be persuaded to display the number of pages in the output PDF and
the total number of systems?
The idea would be to guide the user as to suitable values for

\paper {
  system-count = xx
  page-count = yy
}

without having to count up the number of systems (pages is not really a
problem of course).

Richard Shann