Enable ARM/linux cross compile to use clang.

chrome/test/data/nacl/nameservice/pm_nameservice_test.cc

 /*
  * 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.
  */
 
 /*
  * Post-message based test for simple rpc based access to name services.
  *
  * Converted from srpc_nameservice_test (deprecated), i.e., C -> C++,
@@ skipping 79 matching lines @@
   }
   sb->Printf("NaClSrpcClientCtor succeeded\n");
   close(ns);
   g_ns_channel_initialized = 1;
 }
 
 //
 // Dump RNG output into a string.
 //
 void RngDump(const pp::Var& message_data, nacl::StringBuffer* sb) {
-  NaClSrpcError rpc_result;
+  NaClSrpcError rpc_result __attribute__((unused));
   int status;
   int rng;
 
   Initialize(message_data, sb);
 
   rpc_result = NaClSrpcInvokeBySignature(&g_ns_channel,
                                          NACL_NAME_SERVICE_LOOKUP,
                                          "SecureRandom", O_RDONLY,
                                          &status, &rng);
   assert(NACL_SRPC_RESULT_OK == rpc_result);

[Nico, 2014/08/08 15:28:44]

nit: if this can base, `base::ignore_result(rpc_result);` below the assert is
slightly nicer than the attribute imho

   printf("rpc status %d\n", status);
   assert(NACL_NAME_SERVICE_SUCCESS == status);
   printf("rng descriptor %d\n", rng);
 
   dump_output(sb, rng, RNG_OUTPUT_BYTES);
   close(rng);
 }
 
 void ManifestTest(const pp::Var& message_data, nacl::StringBuffer* sb) {
   int status = -1;
@@ skipping 102 matching lines @@
 };
 
 namespace pp {
 
 // Factory function for your specialization of the Module object.
 Module* CreateModule() {
   return new MyModule();
 }
 
 }  // namespace pp