Generating dependencies for Lilypond

[YTG 1234]

I've been wondering what the equivalent of cpp -M for Lilypond is, if 
there is such a thing.

It wouldn't be so simple to implement; as well as tracking \includes 
recursively, tracking the expected names of output files (as there can 
be multiple per source file) is also required. There's probably some 
Guile interface for getting all the books generated by a file, but there 
would have to be a way to evaluate it without compiling the entire score…

Any ideas?