diff --git a/include/stdlib.h b/include/stdlib.h
index 2c62f091c136..11ac074374dd 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -151,7 +151,7 @@ _Noreturn void	 _Exit(int);
 /*
  * If we're in a mode greater than C99, expose C11 functions.
  */
-#if __ISO_C_VISIBLE >= 2011
+#if __ISO_C_VISIBLE >= 2011 || __cplusplus >= 201103L
 void *	aligned_alloc(size_t, size_t);
 int	at_quick_exit(void (*)(void));
 _Noreturn void