Convert RLZ to a buildflag header

rlz/features/BUILD.gn

Index: rlz/features/BUILD.gn
diff --git a/rlz/features/BUILD.gn b/rlz/features/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..58328e7cf332802dded7982c96783477f35ab771
--- /dev/null
+++ b/rlz/features/BUILD.gn
@@ -0,0 +1,11 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/buildflag_header.gni")
+import("//rlz/features/features.gni")
+
+buildflag_header("features") {
+  header = "features.h"
+  flags = [ "ENABLE_RLZ=$enable_rlz" ]
+}