diff --git a/libc/include/execinfo.h b/libc/include/execinfo.h
index 88f4ae7..84b637c 100644
--- a/libc/include/execinfo.h
+++ b/libc/include/execinfo.h
@@ -47,6 +47,8 @@
  *
  * Available since API level 33.
  */
+
+#if __BIONIC_AVAILABILITY_GUARD(33)
 int backtrace(void* _Nonnull * _Nonnull buffer, int size) __INTRODUCED_IN(33);
 
 /**
@@ -70,5 +72,7 @@
  * Available since API level 33.
  */
 void backtrace_symbols_fd(void* _Nonnull const* _Nonnull buffer, int size, int fd) __INTRODUCED_IN(33);
+#endif /* __BIONIC_AVAILABILITY_GUARD(33) */
+
 
 __END_DECLS