Use nullptr instead of NULL
diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index 0922d75..ea9bde9 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -269,8 +269,8 @@
   feature_infos.shrink (0); /* Done with these */
 
 
-  add_gsub_pause (NULL);
-  add_gpos_pause (NULL);
+  add_gsub_pause (nullptr);
+  add_gpos_pause (nullptr);
 
   for (unsigned int table_index = 0; table_index < 2; table_index++)
   {