diff --git a/libcxx/include/__threading_support b/libcxx/include/__threading_support
--- a/libcxx/include/__threading_support
+++ b/libcxx/include/__threading_support
@@ -16,7 +16,7 @@
 #include <__compare/ordering.h>
 #include <__config>
 #include <__fwd/hash.h>
-#include <__thread/poll_with_backoff.h>
+#include <ctime>
 #include <errno.h>
 #include <iosfwd>
 #include <limits>
@@ -54,7 +54,7 @@
 #define _LIBCPP_NO_THREAD_SAFETY_ANALYSIS
 #endif
 
-typedef ::timespec __libcpp_timespec_t;
+typedef std::timespec __libcpp_timespec_t;
 #endif // !defined(_LIBCPP_HAS_NO_THREADS)
 
 _LIBCPP_BEGIN_NAMESPACE_STD
diff --git a/libcxx/src/support/win32/thread_win32.cpp b/libcxx/src/support/win32/thread_win32.cpp
--- a/libcxx/src/support/win32/thread_win32.cpp
+++ b/libcxx/src/support/win32/thread_win32.cpp
@@ -7,6 +7,8 @@
 //===----------------------------------------------------------------------===//
 
 #include <__threading_support>
+#include <chrono>
+
 #define NOMINMAX
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>