Cleanup: Use Bit('build_ARCH') instead of Bit('target_ARCH')

src/trusted/validator/build.scons

 # -*- python -*-
 # 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.
 
 
 import os
 import sys
 Import('env')
 
 
 env.ComponentLibrary(env.NaClTargetArchSuffix('ncfileutils'), ['ncfileutil.c'])
 
 env.ComponentLibrary('validation_cache', ['validation_cache.c'])
 
 env.ComponentLibrary('validators', ['validator_init.c'])
 
-if env.Bit('target_x86') or env.Bit('target_mips32'):
+if env.Bit('build_x86') or env.Bit('build_mips32'):
   # TODO(ncbray) support ARM.  This will require making validation caching safe
   # for ARM and embedding ARM binary chunks in the test that can trigger various
   # validation scenarios.
   gtest_env = env.MakeGTestEnv()
 
   validation_cache_test_exe = gtest_env.ComponentProgram(
       'validation_cache_test',
       ['validation_cache_test.cc'],
       EXTRA_LIBS=['validators', 'nrd_xfer', 'validation_cache'])
 
   node = gtest_env.CommandTest(
       'validation_cache_test.out',
       command=[validation_cache_test_exe])
 
   env.AddNodeToTestSuite(node, ['small_tests', 'validator_tests'],
                          'run_validation_cache_test')