turning off spurious warnings

[Michael Vanier]

I've just started working with Lilypond 1.7.13, after a long absence from
lilypond use.  I notice that I get warnings if I have empty lyrics that
don't match a notehead (say, they match a rest).  For empty lyrics I just
put in an empty string (""), which works, but then Lilypond treats that as
a "real" lyric and raises the unnecessary warning when the empty string
matches a rest.  Is there a way to get around this?

Another odd warning I got was this:

Calculating line breaks... programming error: No StaffSpacing wishes found
(Continuing; cross thumbs)

It didn't seem to cause any problems.  What does this mean, and how do I
fix it?

Thanks,

Mike