Fix the lowlevel test with the batteries USE flag

--- a/test_pgocaml_lowlevel.ml	2012-04-10 20:45:04.000000000 +0200
+++ b/test_pgocaml_lowlevel.ml	2012-09-15 16:45:37.104790274 +0200
@@ -22,7 +22,11 @@
 
 open Printf
 
+IFDEF USE_BATTERIES THEN
+module List = BatList
+ELSE
 open ExtList
+ENDIF
 
 let print_row i row =
   printf "row %d: [%s]\n" i
--- a/Makefile	2012-07-04 19:53:31.000000000 +0200
+++ b/Makefile	2012-09-15 17:00:58.384820257 +0200
@@ -84,7 +84,7 @@
 #
 
 test_pgocaml_lowlevel$(EXECUTABLE_SUFFIX): test_pgocaml_lowlevel.cmo pgocaml.cma
-	ocamlfind ocamlc $(OCAMLCFLAGS) $(OCAMLCPACKAGES) $(OCAMLCLIBS) pgocaml.cma -o $@ $<
+	ocamlfind ocamlc $(OCAMLCFLAGS) $(OCAMLSYNTAX) $(OCAMLCPACKAGES) $(OCAMLCLIBS) pgocaml.cma -o $@ $<
 
 test_pgocaml$(EXECUTABLE_SUFFIX): test_pgocaml.cmo pgocaml.cma
 	ocamlfind ocamlc $(OCAMLCFLAGS) $(OCAMLCPACKAGES) $(OCAMLCLIBS) pgocaml.cma -o $@ $<