ignore py3_test_grammar when compiling the library
diff --git a/Makefile.pre.in b/Makefile.pre.in
index f99d1e1..f8415a7 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -892,11 +892,13 @@
 	PYTHONPATH=$(DESTDIR)$(LIBDEST)  $(RUNSHARED) \
 		./$(BUILDPYTHON) -Wi -tt $(DESTDIR)$(LIBDEST)/compileall.py \
 		-d $(LIBDEST) -f \
-		-x 'bad_coding|badsyntax|site-packages' $(DESTDIR)$(LIBDEST)
+		-x 'bad_coding|badsyntax|site-packages|py3_test_grammar' \
+		$(DESTDIR)$(LIBDEST)
 	PYTHONPATH=$(DESTDIR)$(LIBDEST) $(RUNSHARED) \
 		./$(BUILDPYTHON) -Wi -tt -O $(DESTDIR)$(LIBDEST)/compileall.py \
 		-d $(LIBDEST) -f \
-		-x 'bad_coding|badsyntax|site-packages' $(DESTDIR)$(LIBDEST)
+		-x 'bad_coding|badsyntax|site-packages|py3_test_grammar' \
+		$(DESTDIR)$(LIBDEST)
 	-PYTHONPATH=$(DESTDIR)$(LIBDEST)  $(RUNSHARED) \
 		./$(BUILDPYTHON) -Wi -t $(DESTDIR)$(LIBDEST)/compileall.py \
 		-d $(LIBDEST)/site-packages -f \