I am trying to prepare a text with pdflatex which incorporates a
lilypond file. I'm working in cygwin. Lilypond-book runs fine, but
when I run pdflatex on the final .tex file, I get a lot of "non-PDF
special ignored" messages during the process. The resulting PDF looks
fine except for the fact that all bar lines, beams, and stems are
missing. How do I fix?