LILYPOND_BOOK = $(script-dir)/lilypond-book.py
LILYPOND_BOOK_INCLUDES = -I $(src-dir)/ -I $(outdir) -I $(input-dir) -I $(input-dir)/regression/ -I $(input-dir)/manual/ -I $(input-dir)/tutorial/ -I $(top-build-dir)/mf/$(outconfbase)/ -I $(top-build-dir)/mf/out/
-LILYPOND_BOOK_LILYPOND_FLAGS=--backend=eps --formats=ps,png,pdf -dinclude-eps-fonts -dgs-load-fonts --header=texidoc -I $(top-src-dir)/input/manual -dcheck-internal-types -ddump-signatures -danti-alias-factor=2
+LILYPOND_JOBS=$(if $(CPU_COUNT),-djob-count=$(CPU_COUNT),)
+LILYPOND_BOOK_LILYPOND_FLAGS=--backend=eps --formats=ps,png,pdf $(LILYPOND_JOBS) -dinclude-eps-fonts -dgs-load-fonts --header=texidoc -I $(top-src-dir)/input/manual -dcheck-internal-types -ddump-signatures -danti-alias-factor=2
LILYPOND_BOOK_FLAGS = --process="$(LILYPOND_BINARY) $(LILYPOND_BOOK_LILYPOND_FLAGS)"
TEXINPUTS=$(top-src-dir)/tex/::