Add nacl-clang testing to SCons

tests/stubout_mode/nacl.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('env')
 
 if 'TRUSTED_ENV' not in env:
   Return()
 
 # Even if stubout mode is not supported sel_ldr still must run valid .nexes.
 hello_world_nexe = env.File('${STAGING_DIR}/hello_world${PROGSUFFIX}')
 node = env.CommandSelLdrTestNacl(
     'hello_world_stub_out_run.out', hello_world_nexe,
     sel_ldr_flags=['-s'])
 env.AddNodeToTestSuite(
     node, ['small_tests'], 'run_valid_nexe_with_stubout_test')
 
 # Do not run these tests with pexes, assuming they are portable, since
 # they use inline assembler.
 if env.Bit('bitcode') and env.Bit('pnacl_generate_pexe'):
   Return()
 
+# nacl-clang currently has trouble with the top-level asm in this file:
+# https://code.google.com/p/nativeclient/issues/detail?id=3968
+if env.Bit('nacl_clang'):
+  Return()
+
 # The file partly_invalid.c contains inline assembler
 if env.Bit('bitcode'):
   env.AddBiasForPNaCl()
   env.PNaClForceNative()
 
 # Newlib + PIC doesn't provide native ___tls_get_addr, so gold complains.
 if env.Bit('bitcode') and env.Bit('nacl_pic'):
   Return()
 
 # TODO(mseaborn): Extend the ARM validator to support this.
@@ skipping 74 matching lines @@
 # offline should be equivalent to using sel_ldr's "-s" option.
 # This tool exists only for x86.
 node = env.CommandSelLdrTestNacl(
     'partly_invalid_stubout.out',
     partly_invalid_stubout_nexe,
     stdout_golden=env.File('with_stubout.stdout'),
     exit_status='untrusted_sigsegv')
 env.AddNodeToTestSuite(node, test_suites, 'run_offline_stubout_test',
                        is_broken=(env.Bit('target_mips32') or
                                   testing_on_asan_or_valgrind))