diff --git a/libcxx/include/__threading_support b/libcxx/include/__threading_support
--- a/libcxx/include/__threading_support
+++ b/libcxx/include/__threading_support
@@ -16,7 +16,6 @@
 #include <__compare/ordering.h>
 #include <__config>
 #include <__fwd/hash.h>
-#include <__thread/poll_with_backoff.h>
 #include <errno.h>
 #include <iosfwd>
 #include <limits>