Add ARM toolchain support.

build_tools/bots/pnacl_bots.sh

 #!/bin/bash
 # Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 
 ######################################################################
 # Notes on directory layout:
 # makefile location (base_dir):  naclports/src
 # bot script location:           naclports/src/build_tools/bots/
 # toolchain injection point:     specified externally via NACL_SDK_ROOT.
 ######################################################################
 
 set -o nounset
 set -o errexit
 
 readonly BASE_DIR="$(dirname $0)/../.."
 cd ${BASE_DIR}
 
 ERROR=0
 
-export NACL_PACKAGES_BITSIZE=pnacl
+export NACL_ARCH=pnacl
 readonly PACKAGES=$(make works_for_pnacl_list)
 
 
 StepConfig() {
   echo "@@@BUILD_STEP CONFIG"
   echo "BASE_DIR: ${BASE_DIR}"
   echo "PACKAGES:"
   for i in ${PACKAGES} ; do
     echo "    $i"
   done
@@ skipping 23 matching lines @@
     echo "@@@STEP_FAILURE@@@"
   fi
   echo -e "${messages}"
 }
 
 StepConfig
 StepInstallSdk
 StepBuildEverything
 
 exit ${ERROR}