$(PYTHON) $(LILYPOND_BOOK) $(LILYPOND_BOOK_INCLUDES) \
--process='$(LILYPOND_BOOK_PROCESS) \
$(LILYPOND_BOOK_LILYPOND_FLAGS)' --output=$(outdir) \
- $(LILYPOND_BOOK_FLAGS)
+ --redirect-lilypond-output $(LILYPOND_BOOK_FLAGS)
HTML_FILES = $(call src-wildcard,*.html)
HTMLY_FILES = $(call src-wildcard,*.htmly)