Add nacl-clang testing to SCons

tests/fixedfeaturecpu/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.
 
 # Tests for Native Client fixed-feature CPU mode. The fixed-feature CPU
 # mode requires SSE and disallows MMX and x87. By fixing the instruction set
 # it allows exclusion of the CPUID instruction and use of a read-only text
 # segment. See http://code.google.com/p/nativeclient/issues/detail?id=2684
 Import('env')
@@ skipping 102 matching lines @@
       'ff_hello_world_sse_Z.out', ff_hello_world_sse_nexe,
       exit_status=expect_sse_Z_status,
       sel_ldr_flags=['-Z'])
   env.AddNodeToTestSuite(node, test_suites, 'run_ff_sse_Z_test',
                          is_broken=is_validation_broken)
 
 # NOTE: -mfpmath=387 does not work for x86-64. See:
 # http://code.google.com/p/nativeclient/issues/detail?id=2692
 if not env.Bit('target_x86_64') and not env.Bit('bitcode'):
   x87_env = env.Clone()
-  x87_env.Append(CCFLAGS=['-mfpmath=387'])
+  x87_env.Append(CCFLAGS=['-mfpmath=387', '-mno-sse'])
   x87_o = x87_env.ComponentObject('ff_hello_world_x87.o', 'ff_hello_world.c')
   ff_hello_world_x87_nexe = x87_env.ComponentProgram(
       'ff_hello_world_x87',
       'ff_hello_world_x87.o',
       EXTRA_LIBS=['${NONIRT_LIBS}'])
 
   # ff_hello_world_x87 should pass in default mode
   node = env.CommandSelLdrTestNacl(
       'ff_hello_world_x87.out', ff_hello_world_x87_nexe,
       stdout_golden=env.File('ff_hello_world.stdout'))
   env.AddNodeToTestSuite(node, test_suites, 'run_ff_x87_test')
 
   # ff_hello_world_x87 should fail in fixed function CPU mode
   node = env.CommandSelLdrTestNacl(
       'ff_hello_world_x87_Z.out', ff_hello_world_x87_nexe,
       exit_status=expect_x87_Z_status,
       sel_ldr_flags=['-Z'])
   env.AddNodeToTestSuite(node, test_suites, 'run_ff_x87_Z_test',
                          is_broken=is_validation_broken)