# rules for directories with MusicXML files.
-MUSICXML_FILES := $(call src-wildcard,*.xml)
-MUSICMXL_FILES := $(call src-wildcard,*.mxl) # Allow .mxl for compressed files
-OUT_LY_FILES = $(sort ${MUSICXML_FILES:%.xml=$(outdir)/%.ly} ${MUSICMXL_FILES:%.mxl=$(outdir)/%.ly})
+MUSICXML_FILES = $(call src-wildcard,*.xml)
+MUSICMXL_FILES = $(call src-wildcard,*.mxl) # Allow .mxl for compressed files
+OUT_LY_FILES = $(sort ${MUSICXML_FILES:%.xml=$(outdir)/%.ly} ${MUSICMXL_FILES:%.mxl=$(outdir)/%.ly} ${EXTRA_OUT_LY_FILES})
OUT_FILES = $(OUT_LY_FILES)
EXTRA_DIST_FILES += $(MUSICXML_FILES) $(MUSICMXL_FILES)