diff --git a/sys/sys/stdatomic.h b/sys/sys/stdatomic.h
--- a/sys/sys/stdatomic.h
+++ b/sys/sys/stdatomic.h
@@ -163,6 +163,11 @@
 #endif
 }
 
+#if defined(__cplusplus) && !defined(_Bool)
+#define	_Bool	bool
+#define	__bool_locally_defined
+#endif
+
 /*
  * 7.17.5 Lock-free property.
  */
@@ -406,4 +411,9 @@
 }
 #endif /* !_KERNEL */
 
+#ifdef __bool_locally_defined
+#undef _Bool
+#undef __bool_locally_defined
+#endif
+
 #endif /* !_STDATOMIC_H_ */