diff --git a/libc/include/sys/cdefs.h b/libc/include/sys/cdefs.h
index 2bd058e..24b341e 100644
--- a/libc/include/sys/cdefs.h
+++ b/libc/include/sys/cdefs.h
@@ -451,15 +451,21 @@
 
 #ifdef __clang__
 #define __AVAILABILITY(...) __attribute__((availability(android,__VA_ARGS__)))
+#else
+#define __AVAILABILITY(...)
+#endif // __clang__
+
 #define __INTRODUCED_IN(api_level) __AVAILABILITY(introduced=api_level)
 #define __DEPRECATED_IN(api_level) __AVAILABILITY(deprecated=api_level)
 #define __REMOVED_IN(api_level) __AVAILABILITY(obsoleted=api_level)
+
+#if __LP64__
+#define __INTRODUCED_IN_32(api_level)
+#define __INTRODUCED_IN_64 __INTRODUCED_IN
 #else
-#define __AVAILABILITY(...)
-#define __INTRODUCED_IN(api_level)
-#define __DEPRECATED_IN(api_level)
-#define __REMOVED_IN(api_level)
-#endif // __clang__
+#define __INTRODUCED_IN_32 __INTRODUCED_IN
+#define __INTRODUCED_IN_64(api_level)
+#endif
 
 #if __has_builtin(__builtin_umul_overflow) || __GNUC__ >= 5
 #if __LP64__