diff --git a/include/ConflictSet.h b/include/ConflictSet.h
index 0b91d6a..f02c9ee 100644
--- a/include/ConflictSet.h
+++ b/include/ConflictSet.h
@@ -132,7 +132,7 @@ struct __attribute__((__visibility__("default"))) ConflictSet {
 
 private:
   Impl *impl;
-#if defined(__cplusplus) && __cplusplus <= 199711L
+#if __cplusplus <= 199711L
   /* Declared private and left undefined to prevent copying in C++98/C++03.
      The compiler would otherwise implicitly generate public copy operations,
      which share the opaque Impl* and cause a double-free. */