Add nacl-clang testing to SCons

tests/toolchain/synchronization_cpp11.cc

 /*
  * Copyright (c) 2013 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.
  */
 
 /*
  * This test ensures that the PNaCl backends can deal with C++11
  * synchronization primitives as would be written by regular users,
  * including PNaCl's ABI stabilization and target lowering.
@@ skipping 28 matching lines @@
 
 
 /*
  * ATOMIC_*_LOCK_FREE
  *
  * These macros must be compile-time constants, and for PNaCl the value
  * should be 1, which means that the corresponding type may be
  * lock-free: we can't guarantee that all our platforms are lock-free.
  */
 void test_lock_free_macros() {
+#if defined(__pnacl__)
   static_assert(ATOMIC_BOOL_LOCK_FREE == 1, "should be compile-time 1");
   static_assert(ATOMIC_CHAR_LOCK_FREE == 1, "should be compile-time 1");
   static_assert(ATOMIC_CHAR16_T_LOCK_FREE == 1, "should be compile-time 1");
   static_assert(ATOMIC_CHAR32_T_LOCK_FREE == 1, "should be compile-time 1");
   static_assert(ATOMIC_WCHAR_T_LOCK_FREE == 1, "should be compile-time 1");
   static_assert(ATOMIC_SHORT_LOCK_FREE == 1, "should be compile-time 1");
   static_assert(ATOMIC_INT_LOCK_FREE == 1, "should be compile-time 1");
   static_assert(ATOMIC_LONG_LOCK_FREE == 1, "should be compile-time 1");
   static_assert(ATOMIC_LLONG_LOCK_FREE == 1, "should be compile-time 1");
   static_assert(ATOMIC_POINTER_LOCK_FREE == 1, "should be compile-time 1");
+#elif defined(__x86_64__) || defined(__i386__) || defined(__arm__)
+  static_assert(ATOMIC_BOOL_LOCK_FREE == 2, "should be compile-time 2");
+  static_assert(ATOMIC_CHAR_LOCK_FREE == 2, "should be compile-time 2");
+  static_assert(ATOMIC_CHAR16_T_LOCK_FREE == 2, "should be compile-time 2");
+  static_assert(ATOMIC_CHAR32_T_LOCK_FREE == 2, "should be compile-time 2");
+  static_assert(ATOMIC_WCHAR_T_LOCK_FREE == 2, "should be compile-time 2");
+  static_assert(ATOMIC_SHORT_LOCK_FREE == 2, "should be compile-time 2");
+  static_assert(ATOMIC_INT_LOCK_FREE == 2, "should be compile-time 2");
+  static_assert(ATOMIC_LONG_LOCK_FREE == 2, "should be compile-time 2");
+  static_assert(ATOMIC_LLONG_LOCK_FREE == 2, "should be compile-time 2");
+  static_assert(ATOMIC_POINTER_LOCK_FREE == 2, "should be compile-time 2");
+# else
+  // TODO: Other architechtures, such as mips
+#endif
 }
 
 #define TEST_IS_LOCK_FREE(TYPE) do {                    \
     CHECK_EQ(std::atomic<TYPE>().is_lock_free(), true,  \
              "expected lock-free for `" STR(TYPE) "`"); \
   } while (0)
 
 void test_is_lock_free() {
   TEST_IS_LOCK_FREE(bool);
   // Table 145.
@@ skipping 41 matching lines @@
 //   - std::atomic and their functions (including is_lock_free).
 //   - std::atomic_flag.
 //   - std::atomic_thread_fence (atomic_signal_fence currently unsupported).
 //   - 6 memory orders.
 
 int main() {
   test_lock_free_macros();
   test_is_lock_free();
   return 0;
 }