Index: ocamlgraph-0.99b/Makefile.in
===================================================================
--- ocamlgraph-0.99b.orig/Makefile.in
+++ ocamlgraph-0.99b/Makefile.in
@@ -208,10 +208,14 @@ install-byte: 
 install-opt: install-byte
 	cp -f graph$(LIBEXT) graph.cmx $(CMXA) "$(OCAMLLIB)"
 
+ifneq ($(OCAMLOPT),no)
+INSTALL_OPT=graph$(LIBEXT) graph.cmx $(CMXA)
+endif
+
 install-findlib: META
 ifdef OCAMLFIND
-	$(OCAMLFIND) install ocamlgraph META *.mli \
-		graph$(LIBEXT) graph.cmx graph.cmo graph.cmi $(CMA) $(CMXA)
+	$(OCAMLFIND) install ocamlgraph META src/*.mli lib/*.mli \
+		$(INSTALL_OPT) graph.cmo graph.cmi $(CMA)
 endif
 
 # documentation