diff --git a/internal/ceres/context_impl.cc b/internal/ceres/context_impl.cc
index 1b9662f..20fe5cb 100644
--- a/internal/ceres/context_impl.cc
+++ b/internal/ceres/context_impl.cc
@@ -34,10 +34,9 @@
 namespace internal {
 
 void ContextImpl::EnsureMinimumThreads(int num_threads) {
-#ifdef CERES_USE_CXX11_THREADS
+#ifdef CERES_USE_CXX_THREADS
   thread_pool.Resize(num_threads);
-#endif  // CERES_USE_CXX11_THREADS
-
+#endif  // CERES_USE_CXX_THREADS
 }
 }  // namespace internal
 }  // namespace ceres