etc.o : etc.c constdefs.h $(HDRS) $(ruby_headers) \
  $(hdrdir)/ruby/io.h \
  $(hdrdir)/ruby/encoding.h \
  $(hdrdir)/ruby/oniguruma.h

constdefs.h : $(srcdir)/mkconstants.rb
	@echo "generating constant definitions"
	@$(RUBY) $(srcdir)/mkconstants.rb -o constdefs.h