Remove redundant void from C++ sources (#1486)

src/hb-ot-map.cc

diff --git a/src/hb-ot-map.cc b/src/hb-ot-map.cc
index 95f794a..884202c 100644
--- a/src/hb-ot-map.cc
+++ b/src/hb-ot-map.cc
@@ -68,7 +68,7 @@
   }
 }
 
-hb_ot_map_builder_t::~hb_ot_map_builder_t (void)
+hb_ot_map_builder_t::~hb_ot_map_builder_t ()
 {
   feature_infos.fini ();
   for (unsigned int table_index = 0; table_index < 2; table_index++)