+not the directory containing the included file. However,
+this behavior can be changed by passing the option
+@code{-drelative-includes} option at the command line
+(or by adding @code{#(ly:set-option 'relative-includes #t)}
+at the top of the main input file). With @code{relative-includes}
+set, the path for each @code{\include} command will be taken
+relative to the file containing that command. This behavior is
+recommended and it will become the default behavior in a future
+version of lilypond.