diff -ruN stepmake/stepmake/c++-rules.make lilypond-2.7.11/stepmake/stepmake/c++-rules.make
--- stepmake/stepmake/c++-rules.make	2005-10-02 09:14:45.000000000 -0700
+++ stepmake/stepmake/c++-rules.make	2005-10-02 09:15:10.000000000 -0700
@@ -26,6 +26,7 @@
 
 $(outdir)/%.cc: %.ll
 	$(FLEX) -Cfe -p -p -o$@ $< 
+	perl -i.bak -pe 's/^class istream;/#include <iostream>;\nusing namespace std;/' $@
 
 $(outdir)/%-rc.o: $(outdir)/%.rc
 	$(WINDRES) $(WINDRES_FLAGS) -o$@ $<