[glyf] Limit points in a glyf to 10000 roughly

Only enforced when components are being expanded.

Fixes https://github.com/harfbuzz/harfbuzz/issues/3838

src/OT/glyf/Glyph.hh

@@ -16,6 +16,11 @@ struct glyf_accelerator_t;
 namespace glyf_impl {
 
 
+#ifndef HB_GLYF_MAX_POINTS
+#define HB_GLYF_MAX_POINTS 10000
+#endif
+
+
 enum phantom_point_index_t
 {
   PHANTOM_LEFT   = 0,
@@ -313,6 +318,9 @@ struct Glyph
 	  for (unsigned int i = 0; i < PHANTOM_COUNT; i++)
 	    phantoms[i] = comp_points[comp_points.length - PHANTOM_COUNT + i];
 
+	if (all_points.length > HB_GLYF_MAX_POINTS)
+	  return false;
+
 	all_points.extend (comp_points.sub_array (0, comp_points.length - PHANTOM_COUNT));
 
 	comp_index++;