Add normalize mode

In preparation for Hangul shaper.
diff --git a/src/Makefile.am b/src/Makefile.am
index c70e198..d64efdf 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -70,6 +70,7 @@
 	hb-ot-shape-complex-indic-table.hh \
 	hb-ot-shape-complex-misc.cc \
 	hb-ot-shape-complex-private.hh \
+	hb-ot-shape-normalize-private.hh \
 	hb-ot-shape-normalize.cc \
 	hb-ot-shape-private.hh \
 	$(NULL)