Remove NaCl support.

src/base/atomicops.h

Index: src/base/atomicops.h
diff --git a/src/base/atomicops.h b/src/base/atomicops.h
index ea33e489285d8d5fc2f62ad8f2b54d64650fc8bb..973e96b9ea5aad16b79d06474a2551ee3f289418 100644
--- a/src/base/atomicops.h
+++ b/src/base/atomicops.h
@@ -42,17 +42,15 @@ namespace base {
 
 typedef char Atomic8;
 typedef int32_t Atomic32;
-#if defined(__native_client__)
-typedef int64_t Atomic64;
-#elif defined(V8_HOST_ARCH_64_BIT)
+#if defined(V8_HOST_ARCH_64_BIT)
 // We need to be able to go between Atomic64 and AtomicWord implicitly.  This
 // means Atomic64 and AtomicWord should be the same type on 64-bit.
 #if defined(__ILP32__)
 typedef int64_t Atomic64;
 #else
 typedef intptr_t Atomic64;
+#endif  // defined(__ILP32__)
 #endif  // defined(V8_HOST_ARCH_64_BIT)
-#endif  // defined(__native_client__)
 
 // Use AtomicWord for a machine-sized pointer.  It will use the Atomic32 or
 // Atomic64 routines below, depending on your architecture.
@@ -143,8 +141,6 @@ Atomic64 Release_Load(volatile const Atomic64* ptr);
 #include "src/base/atomicops_internals_x86_msvc.h"
 #elif defined(__APPLE__)
 #include "src/base/atomicops_internals_mac.h"
-#elif defined(__native_client__)
-#include "src/base/atomicops_internals_portable.h"
 #elif defined(__GNUC__) && V8_HOST_ARCH_ARM64
 #include "src/base/atomicops_internals_arm64_gcc.h"
 #elif defined(__GNUC__) && V8_HOST_ARCH_ARM