Use nullptr instead of NULL

src/hb-ot-shape-complex-indic.cc

diff --git a/src/hb-ot-shape-complex-indic.cc b/src/hb-ot-shape-complex-indic.cc
index c985026..324333c 100644
--- a/src/hb-ot-shape-complex-indic.cc
+++ b/src/hb-ot-shape-complex-indic.cc
@@ -435,7 +435,7 @@
   map->add_gsub_pause (initial_reordering);
   for (; i < INDIC_BASIC_FEATURES; i++) {
     map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ | F_MANUAL_ZWNJ);
-    map->add_gsub_pause (NULL);
+    map->add_gsub_pause (nullptr);
   }
   map->add_gsub_pause (final_reordering);
   for (; i < INDIC_NUM_FEATURES; i++) {
@@ -533,7 +533,7 @@
 {
   indic_shape_plan_t *indic_plan = (indic_shape_plan_t *) calloc (1, sizeof (indic_shape_plan_t));
   if (unlikely (!indic_plan))
-    return NULL;
+    return nullptr;
 
   indic_plan->config = &indic_configs[0];
   for (unsigned int i = 1; i < ARRAY_LENGTH (indic_configs); i++)
@@ -1848,14 +1848,14 @@
   override_features_indic,
   data_create_indic,
   data_destroy_indic,
-  NULL, /* preprocess_text */
-  NULL, /* postprocess_glyphs */
+  nullptr, /* preprocess_text */
+  nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
   decompose_indic,
   compose_indic,
   setup_masks_indic,
-  NULL, /* disable_otl */
-  NULL, /* reorder_marks */
+  nullptr, /* disable_otl */
+  nullptr, /* reorder_marks */
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
   false, /* fallback_position */
 };