Enable ARM/linux cross compile to use clang.

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

Index: chrome/test/data/nacl/nameservice/pm_nameservice_test.cc
diff --git a/chrome/test/data/nacl/nameservice/pm_nameservice_test.cc b/chrome/test/data/nacl/nameservice/pm_nameservice_test.cc
index 24397220ad570db766c120344559f79772a7d260..2a0887b7b4155fee07eb93983db47fc26394c5d6 100644
--- a/chrome/test/data/nacl/nameservice/pm_nameservice_test.cc
+++ b/chrome/test/data/nacl/nameservice/pm_nameservice_test.cc
@@ -97,7 +97,7 @@ void Initialize(const pp::Var& message_data, nacl::StringBuffer* sb) {
 // 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;