diff --git a/libcxx/include/__config b/libcxx/include/__config
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -1152,14 +1152,6 @@
        _LIBCPP_HAS_NO_THREADS is defined.
 #endif
 
-#if defined(__STDCPP_THREADS__) && defined(_LIBCPP_HAS_NO_THREADS)
-#error _LIBCPP_HAS_NO_THREADS cannot be set when __STDCPP_THREADS__ is set.
-#endif
-
-#if !defined(_LIBCPP_HAS_NO_THREADS) && !defined(__STDCPP_THREADS__)
-#define __STDCPP_THREADS__ 1
-#endif
-
 // The glibc and Bionic implementation of pthreads implements
 // pthread_mutex_destroy as nop for regular mutexes. Additionally, Win32
 // mutexes have no destroy mechanism.