\documentclass{article}
\usepackage{graphics}
\begin{document}
Testing lilypond-book tex mode with .latex file suffix.
{%
\parindent 0pt
\noindent
\ifx\preLilyPondExample \undefined
\else
  \expandafter\preLilyPondExample
\fi
\def\lilypondbook{}%
\input{30/lily-10fcfa18-systems.tex}
\ifx\postLilyPondExample \undefined
\else
  \expandafter\postLilyPondExample
\fi
}
\end{document}