diff --git a/assert/assert.h b/assert/assert.h
index 67f1cce5e9..b438d8eeb7 100644
--- a/assert/assert.h
+++ b/assert/assert.h
@@ -135,7 +135,11 @@ __END_DECLS
 #endif /* NDEBUG.  */
 
 
-#if defined __USE_ISOC11 && !defined __cplusplus
+#if (defined __USE_ISOC11			\
+     && (!defined __STDC_VERSION__		\
+	 || __STDC_VERSION__ <= 201710L		\
+	 || !__GNUC_PREREQ (13, 0))		\
+     && !defined __cplusplus)
 # undef static_assert
 # define static_assert _Static_assert
 #endif
diff --git a/sysdeps/pthread/threads.h b/sysdeps/pthread/threads.h
index 687b45c610..13c8f35768 100644
--- a/sysdeps/pthread/threads.h
+++ b/sysdeps/pthread/threads.h
@@ -27,7 +27,9 @@ __BEGIN_DECLS
 #include <bits/thread-shared-types.h>
 #include <bits/types/struct_timespec.h>
 
-#ifndef __cplusplus
+#if (!defined __STDC_VERSION__				\
+     || __STDC_VERSION__ <= 201710L			\
+     || !__GNUC_PREREQ (13, 0)) && !defined __cplusplus
 # define thread_local _Thread_local
 #endif