--- a/gnu/xalloc-oversized.h
+++ b/gnu/xalloc-oversized.h
@@ -52,7 +52,7 @@ typedef size_t __xalloc_count_type;
 #elif ((5 <= __GNUC__ \
         || (__has_builtin (__builtin_mul_overflow) \
             && __has_builtin (__builtin_constant_p))) \
-       && !__STRICT_ANSI__)
+       && !__STRICT_ANSI__) && !defined(__clang__)
 # define xalloc_oversized(n, s) \
    (__builtin_constant_p (n) && __builtin_constant_p (s) \
     ? __xalloc_oversized (n, s) \