This isn’t supported in Dash.
# Figure out the file type of each source file and source include.
ifneq ($(wildcard $(BUILDDIR)/magic.mgc),)
-override types := $(shell $(SED) 's/^ *//;s/ *$$//;s/ {2,}/ /g' <<< $(call quote,$(sourcefiles) $(sourceincludes)) | $(TR) ' ' '\n' | $(FILE) -m $(call quote,$(BUILDDIR)/magic.mgc) --mime-type --separator '|' --files-from - | $(SED) 's/| */|/g')
+override types := $(shell $(PRINTF) '%s\n' $(call quote,$(sourcefiles) $(sourceincludes)) | $(SED) 's/^ *//;s/ *$$//;s/ {2,}/ /g' | $(TR) ' ' '\n' | $(FILE) -m $(call quote,$(BUILDDIR)/magic.mgc) --mime-type --separator '|' --files-from - | $(SED) 's/| */|/g')
endif
# Get the list of supported plaintext file types from the parser.