Fix C++ build

Author: mhlakhani

lib/cpp/src/thrift/Thrift.h

@@ -54,6 +54,9 @@ class TEnumIterator {
 public:
   using iterator_category = std::forward_iterator_tag;
   using value_type = std::pair<int, const char*>;
+  using difference_type = std::ptrdiff_t;
+  using pointer = value_type*;
+  using reference = value_type&;
 
   TEnumIterator(int n, int* enums, const char** names)
     : ii_(0), n_(n), enums_(enums), names_(names) {}