I suppose you could also make $(SOURCES) depend on $(GEN) to save having to remember the "make clean" sometimes. Speaking of clean, the ....out needs cleaning

I suppose you could also make $(SOURCES) depend on $(GEN) to save having to remember the "make clean" sometimes. Speaking of clean, the ....out needs cleaning up too, e.g. "rm -f $(SOURCES:%=%.out)" perhaps (untested).