message: Mark pool::entry for export
diff: @@ -71,7 +71,7 @@ class MONGOCXX_API pool {
  /// @note The lifetime of any entry object must be a subset of the pool object
  /// from which it was acquired.
  ///
  - class entry {
  + class MONGOCXX_API entry {
  public:
  /// Access a member of the client instance.
  client* operator->() const& noexcept;
  