Add include to hopefully fix windows build.

llvm-svn: 186310
diff --git a/llvm/lib/Support/Windows/Path.inc b/llvm/lib/Support/Windows/Path.inc
index 8eee1d2..b023593 100644
--- a/llvm/lib/Support/Windows/Path.inc
+++ b/llvm/lib/Support/Windows/Path.inc
@@ -16,6 +16,7 @@
 //===          is guaranteed to work on *all* Windows variants.
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/STLExtras.h"
 #include "Windows.h"
 #include <fcntl.h>
 #include <io.h>