Support/FileSystem: Add directory_iterator implementation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120989 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Windows/Windows.h b/lib/Support/Windows/Windows.h
index 0233a42..9ee9d1f 100644
--- a/lib/Support/Windows/Windows.h
+++ b/lib/Support/Windows/Windows.h
@@ -94,7 +94,11 @@
     return Handle == InvalidHandle ? 0 : unspecified_bool_true;
   }
 
-  typedef ScopedHandle<HANDLE, INVALID_HANDLE_VALUE,
-                       BOOL (WINAPI*)(HANDLE), ::FindClose>
-    ScopedFindHandle;
+  bool operator!() const {
+    return Handle == InvalidHandle;
+  }
 };
+
+typedef ScopedHandle<HANDLE, INVALID_HANDLE_VALUE,
+                      BOOL (WINAPI*)(HANDLE), ::FindClose>
+  ScopedFindHandle;