[ft] hb_ft_get_glyph_from_name fails for the name of glyph id 0

Based on patch from Jonathan Kew, as reported on the mailing list.

src/hb-ft.cc

@@ -260,6 +260,15 @@ hb_ft_get_glyph_from_name (hb_font_t *font HB_UNUSED,
     *glyph = FT_Get_Name_Index (ft_face, buf);
   }
 
+  if (*glyph == 0)
+  {
+    /* Check whether the given name was actually the name of glyph 0. */
+    char buf[128];
+    if (!FT_Get_Glyph_Name(ft_face, 0, buf, sizeof (buf)) &&
+        len < 0 ? !strcmp (buf, name) : !strncmp (buf, name, len))
+      return true;
+  }
+
   return *glyph != 0;
 }