Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/src/google/protobuf/stubs/atomicops.h

Index: third_party/protobuf/src/google/protobuf/stubs/atomicops.h
diff --git a/third_party/protobuf/src/google/protobuf/stubs/atomicops.h b/third_party/protobuf/src/google/protobuf/stubs/atomicops.h
index 31e2b782350f39e80cd7146134800462c2e6f646..9b3d1e6b57d25ec82ceb25ad8a1baef66ebd5346 100644
--- a/third_party/protobuf/src/google/protobuf/stubs/atomicops.h
+++ b/third_party/protobuf/src/google/protobuf/stubs/atomicops.h
@@ -76,7 +76,7 @@ typedef int32 Atomic32;
 #ifdef GOOGLE_PROTOBUF_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__) || defined(GOOGLE_PROTOBUF_OS_NACL) || defined(GOOGLE_PROTOBUF_ARCH_SPARC)
+#if defined(__ILP32__) || defined(GOOGLE_PROTOBUF_OS_NACL)
 // NaCl's intptr_t is not actually 64-bits on 64-bit!
 // http://code.google.com/p/nativeclient/issues/detail?id=1162
 // sparcv9's pointer type is 32bits
@@ -214,6 +214,8 @@ Atomic64 Release_Load(volatile const Atomic64* ptr);
 #include <google/protobuf/stubs/atomicops_internals_power.h>
 #elif defined(__native_client__)
 #include <google/protobuf/stubs/atomicops_internals_pnacl.h>
+#elif defined(GOOGLE_PROTOBUF_ARCH_PPC)
+#include <google/protobuf/stubs/atomicops_internals_ppc_gcc.h>
 #elif (((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4))
 #include <google/protobuf/stubs/atomicops_internals_generic_gcc.h>
 #elif defined(__clang__)