diff --git a/sys/sys/cdefs.h b/sys/sys/cdefs.h
index d9e1c476f1ef67..080ae0912210d1 100644
--- a/sys/sys/cdefs.h
+++ b/sys/sys/cdefs.h
@@ -278,15 +278,6 @@
 #if (defined(__cplusplus) && __cplusplus >= 201103L) || \
     __has_extension(cxx_static_assert)
 #define	_Static_assert(x, y)	static_assert(x, y)
-#elif __GNUC_PREREQ__(4,6) && !defined(__cplusplus)
-/* Nothing, gcc 4.6 and higher has _Static_assert built-in */
-#elif defined(__COUNTER__)
-#define	_Static_assert(x, y)	__Static_assert(x, __COUNTER__)
-#define	__Static_assert(x, y)	___Static_assert(x, y)
-#define	___Static_assert(x, y)	typedef char __assert_ ## y[(x) ? 1 : -1] \
-				__unused
-#else
-#define	_Static_assert(x, y)	struct __hack
 #endif
 #endif