Add ninja dependency reference to gen written files.

build/toolchain/cros/BUILD.gn

 # Copyright 2014 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/toolchain/clang.gni")
 import("//build/toolchain/gcc_toolchain.gni")
 
 declare_args() {
   # The CrOS build system supports many different kinds of targets across
   # many different architectures. Bringing your own toolchain is also supported,
@@ skipping 11 matching lines @@
   assert(cros_target_cc != "", "Must provide target CC.")
   assert(cros_target_cxx != "", "Must provide target CXX.")
   assert(cros_target_ar != "", "Must provide target AR.")
 
   cc = "${cros_target_cc}"
   cxx = "${cros_target_cxx}"
 
   ar = "${cros_target_ar}"
   ld = cxx
 
+  readelf = "/bin/false"
+  nm = "/bin/false"
+

[Peter Mayo, 2015/07/02 22:12:15]

Bah - remove this.

   toolchain_cpu = "${target_cpu}"
   toolchain_os = "linux"
   is_clang = is_clang
 }