diff --git a/llvm/lib/Support/Windows/WindowsSupport.h b/llvm/include/llvm/Support/Windows/WindowsSupport.h
rename from llvm/lib/Support/Windows/WindowsSupport.h
rename to llvm/include/llvm/Support/Windows/WindowsSupport.h
diff --git a/llvm/lib/Support/CrashRecoveryContext.cpp b/llvm/lib/Support/CrashRecoveryContext.cpp
--- a/llvm/lib/Support/CrashRecoveryContext.cpp
+++ b/llvm/lib/Support/CrashRecoveryContext.cpp
@@ -254,7 +254,7 @@
 // XP, so if support for older versions of Windows is required,
 // it will have to be added.
 
-#include "Windows/WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 
 static LONG CALLBACK ExceptionHandler(PEXCEPTION_POINTERS ExceptionInfo)
 {
diff --git a/llvm/lib/Support/InitLLVM.cpp b/llvm/lib/Support/InitLLVM.cpp
--- a/llvm/lib/Support/InitLLVM.cpp
+++ b/llvm/lib/Support/InitLLVM.cpp
@@ -15,7 +15,7 @@
 #include <string>
 
 #ifdef _WIN32
-#include "Windows/WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 #endif
 
 using namespace llvm;
diff --git a/llvm/lib/Support/RandomNumberGenerator.cpp b/llvm/lib/Support/RandomNumberGenerator.cpp
--- a/llvm/lib/Support/RandomNumberGenerator.cpp
+++ b/llvm/lib/Support/RandomNumberGenerator.cpp
@@ -17,7 +17,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #ifdef _WIN32
-#include "Windows/WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 #else
 #include "Unix/Unix.h"
 #endif
diff --git a/llvm/lib/Support/Windows/DynamicLibrary.inc b/llvm/lib/Support/Windows/DynamicLibrary.inc
--- a/llvm/lib/Support/Windows/DynamicLibrary.inc
+++ b/llvm/lib/Support/Windows/DynamicLibrary.inc
@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 #include "llvm/Support/ConvertUTF.h"
 #include "llvm/Support/raw_ostream.h"
 
diff --git a/llvm/lib/Support/Windows/Host.inc b/llvm/lib/Support/Windows/Host.inc
--- a/llvm/lib/Support/Windows/Host.inc
+++ b/llvm/lib/Support/Windows/Host.inc
@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 #include <cstdio>
 #include <string>
 
diff --git a/llvm/lib/Support/Windows/Memory.inc b/llvm/lib/Support/Windows/Memory.inc
--- a/llvm/lib/Support/Windows/Memory.inc
+++ b/llvm/lib/Support/Windows/Memory.inc
@@ -17,7 +17,7 @@
 #include "llvm/Support/WindowsError.h"
 
 // The Windows.h header must be the last one included.
-#include "WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 
 static DWORD getWindowsProtectionFlags(unsigned Flags) {
   switch (Flags & llvm::sys::Memory::MF_RWE_MASK) {
diff --git a/llvm/lib/Support/Windows/Path.inc b/llvm/lib/Support/Windows/Path.inc
--- a/llvm/lib/Support/Windows/Path.inc
+++ b/llvm/lib/Support/Windows/Path.inc
@@ -25,7 +25,7 @@
 
 // These two headers must be included last, and make sure shlobj is required
 // after Windows.h to make sure it picks up our definition of _WIN32_WINNT
-#include "WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 #include <shellapi.h>
 #include <shlobj.h>
 
diff --git a/llvm/lib/Support/Windows/Process.inc b/llvm/lib/Support/Windows/Process.inc
--- a/llvm/lib/Support/Windows/Process.inc
+++ b/llvm/lib/Support/Windows/Process.inc
@@ -19,7 +19,7 @@
 #include <malloc.h>
 
 // The Windows.h header must be after LLVM and standard headers.
-#include "WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 
 #include <direct.h>
 #include <io.h>
diff --git a/llvm/lib/Support/Windows/Program.inc b/llvm/lib/Support/Windows/Program.inc
--- a/llvm/lib/Support/Windows/Program.inc
+++ b/llvm/lib/Support/Windows/Program.inc
@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/ConvertUTF.h"
 #include "llvm/Support/Errc.h"
diff --git a/llvm/lib/Support/Windows/Signals.inc b/llvm/lib/Support/Windows/Signals.inc
--- a/llvm/lib/Support/Windows/Signals.inc
+++ b/llvm/lib/Support/Windows/Signals.inc
@@ -23,7 +23,7 @@
 #include "llvm/Support/raw_ostream.h"
 
 // The Windows.h header must be after LLVM and standard headers.
-#include "WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 
 #ifdef __MINGW32__
  #include <imagehlp.h>
diff --git a/llvm/lib/Support/Windows/ThreadLocal.inc b/llvm/lib/Support/Windows/ThreadLocal.inc
--- a/llvm/lib/Support/Windows/ThreadLocal.inc
+++ b/llvm/lib/Support/Windows/ThreadLocal.inc
@@ -15,7 +15,7 @@
 //===          is guaranteed to work on *all* Win32 variants.
 //===----------------------------------------------------------------------===//
 
-#include "WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 #include "llvm/Support/ThreadLocal.h"
 
 namespace llvm {
diff --git a/llvm/lib/Support/Windows/Threading.inc b/llvm/lib/Support/Windows/Threading.inc
--- a/llvm/lib/Support/Windows/Threading.inc
+++ b/llvm/lib/Support/Windows/Threading.inc
@@ -13,7 +13,7 @@
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
 
-#include "WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 #include <process.h>
 
 #include <bitset>
diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -60,7 +60,7 @@
 
 #ifdef _WIN32
 #include "llvm/Support/ConvertUTF.h"
-#include "Windows/WindowsSupport.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
 #endif
 
 using namespace llvm;
diff --git a/llvm/tools/llvm-ar/llvm-ar.cpp b/llvm/tools/llvm-ar/llvm-ar.cpp
--- a/llvm/tools/llvm-ar/llvm-ar.cpp
+++ b/llvm/tools/llvm-ar/llvm-ar.cpp
@@ -46,8 +46,7 @@
 #endif
 
 #ifdef _WIN32
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
+#include "llvm/Support/Windows/WindowsSupport.h"
 #endif
 
 using namespace llvm;