Move files from the secondary GN directory to build.

tools/gn/secondary/build/config/mac/BUILD.gn

Index: tools/gn/secondary/build/config/mac/BUILD.gn
diff --git a/tools/gn/secondary/build/config/mac/BUILD.gn b/tools/gn/secondary/build/config/mac/BUILD.gn
deleted file mode 100644
index 78c106aebf96ef39bef525ef3ab6dbd36e57b483..0000000000000000000000000000000000000000
--- a/tools/gn/secondary/build/config/mac/BUILD.gn
+++ /dev/null
@@ -1,10 +0,0 @@
-# Copyright (c) 2013 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.
-
-# On Mac, this is used for everything except static libraries.
-config("mac_dynamic_flags") {
-  ldflags = [
-    "-Wl,-search_paths_first",
-  ]
-}