diff --git a/third_party/expat/include/expat_config/expat_config.h b/third_party/expat/include/expat_config/expat_config.h
index 795b5aaf0e..4968b01756 100644
--- a/third_party/expat/include/expat_config/expat_config.h
+++ b/third_party/expat/include/expat_config/expat_config.h
@@ -11,7 +11,7 @@
 /* #undef HAVE_ARC4RANDOM */
 
 /* Define to 1 if you have the `arc4random_buf' function. */
-#define HAVE_ARC4RANDOM_BUF 1
+/* #define HAVE_ARC4RANDOM_BUF 1 */
 
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #define HAVE_DLFCN_H 1