diff --git a/include/llvm/Config/config.h.cmake b/include/llvm/Config/config.h.cmake
index 1dfa6edb526..996f9ba29a1 100644
--- a/include/llvm/Config/config.h.cmake
+++ b/include/llvm/Config/config.h.cmake
@@ -25,7 +25,7 @@
 #cmakedefine ENABLE_TIMESTAMPS ${ENABLE_TIMESTAMPS}
 
 /* Define to 1 if you have the `arc4random' function. */
-#cmakedefine HAVE_ARC4RANDOM
+#cmakedefine HAVE_DECL_ARC4RANDOM ${HAVE_DECL_ARC4RANDOM}
 
 /* Define to 1 if you have the `backtrace' function. */
 #cmakedefine HAVE_BACKTRACE ${HAVE_BACKTRACE}