Index: assert.h
===================================================================
RCS file: /cvsroot/src/include/assert.h,v
retrieving revision 1.23
diff -u -r1.23 assert.h
--- assert.h	22 May 2019 21:25:01 -0000	1.23
+++ assert.h	24 May 2019 02:59:25 -0000
@@ -105,8 +105,10 @@
 __END_DECLS
 #endif /* __ASSERT_DECLARED */
 
-#if defined(_ISOC11_SOURCE) || (__STDC_VERSION__ - 0) >= 201101L
 #ifndef static_assert
+#if defined(_ISOC11_SOURCE) || (__STDC_VERSION__ - 0) >= 201101L
 #define static_assert _Static_assert
+#elif (__cplusplus - 0) < 201103L
+#define static_assert(x, y) __CTASSERT(x)
 #endif /* static_assert */
 #endif