Update phmap::Hash so that std::hash<Foo*> can be overridden - issue #168

parallel_hashmap/phmap.h

@@ -4426,7 +4426,9 @@ struct HashEq<T*>
         using is_transparent = void;
         template <class U>
         size_t operator()(const U& ptr) const {
-            return phmap::Hash<const T*>{}(HashEq::ToPtr(ptr));
+            // we want phmap::Hash<T*> and not phmap::Hash<const T*>
+            // so "struct std::hash<T*> " override works
+            return phmap::Hash<T*>{}((T*)(uintptr_t)HashEq::ToPtr(ptr));
         }
     };