Index: libcxx/include/thread
===================================================================
--- libcxx/include/thread
+++ libcxx/include/thread
@@ -14,7 +14,7 @@
 
     thread synopsis
 
-#define __STDCPP_THREADS__ __cplusplus
+#define __STDCPP_THREADS__ 1
 
 namespace std
 {
@@ -107,7 +107,7 @@
 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>
 
-#define __STDCPP_THREADS__ __cplusplus
+#define __STDCPP_THREADS__ 1
 
 #ifdef _LIBCPP_HAS_NO_THREADS
 #error <thread> is not supported on this single threaded system
Index: libcxx/test/std/thread/macro.pass.cpp
===================================================================
--- libcxx/test/std/thread/macro.pass.cpp
+++ libcxx/test/std/thread/macro.pass.cpp
@@ -10,7 +10,7 @@
 
 // <thread>
 
-// #define __STDCPP_THREADS__ __cplusplus
+// #define __STDCPP_THREADS__ 1
 
 #include <thread>