diff --git a/absl/base/internal/cycleclock.h b/absl/base/internal/cycleclock.h
index 794564e..a18b584 100644
--- a/absl/base/internal/cycleclock.h
+++ b/absl/base/internal/cycleclock.h
@@ -44,7 +44,10 @@
 
 #include <cstdint>
 
+#include "absl/base/config.h"
+
 namespace absl {
+ABSL_NAMESPACE_BEGIN
 namespace base_internal {
 
 // -----------------------------------------------------------------------------
@@ -85,6 +88,7 @@
 };
 
 }  // namespace base_internal
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif  // ABSL_BASE_INTERNAL_CYCLECLOCK_H_