Update //third_party/protobuf to version 3.

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

Index: third_party/protobuf/src/google/protobuf/stubs/platform_macros.h
diff --git a/third_party/protobuf/src/google/protobuf/stubs/platform_macros.h b/third_party/protobuf/src/google/protobuf/stubs/platform_macros.h
index 30604782c905e765128a95d584d814ab4946f9e2..580263e72e260bc6a60f874cf47d7fae30bbddfc 100644
--- a/third_party/protobuf/src/google/protobuf/stubs/platform_macros.h
+++ b/third_party/protobuf/src/google/protobuf/stubs/platform_macros.h
@@ -1,6 +1,6 @@
 // Protocol Buffers - Google's data interchange format
 // Copyright 2012 Google Inc.  All rights reserved.
-// http://code.google.com/p/protobuf/
+// https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
@@ -31,7 +31,8 @@
 #ifndef GOOGLE_PROTOBUF_PLATFORM_MACROS_H_
 #define GOOGLE_PROTOBUF_PLATFORM_MACROS_H_
 
-#include <google/protobuf/stubs/common.h>
+#define GOOGLE_PROTOBUF_PLATFORM_ERROR \
+#error "Host platform was not detected as supported by protobuf"
 
 // Processor architecture detection.  For more info on what's defined, see:
 //   http://msdn.microsoft.com/en-us/library/b0084kay.aspx
@@ -62,17 +63,60 @@
 #endif
 #elif defined(__pnacl__)
 #define GOOGLE_PROTOBUF_ARCH_32_BIT 1
-#elif defined(__ppc__)
-#define GOOGLE_PROTOBUF_ARCH_PPC 1
+#elif defined(sparc)
+#define GOOGLE_PROTOBUF_ARCH_SPARC 1
+#ifdef SOLARIS_64BIT_ENABLED
+#define GOOGLE_PROTOBUF_ARCH_64_BIT 1
+#else
 #define GOOGLE_PROTOBUF_ARCH_32_BIT 1
+#endif
+#elif defined(_POWER) || defined(__powerpc64__) || defined(__PPC64__)
+#define GOOGLE_PROTOBUF_ARCH_POWER 1
+#define GOOGLE_PROTOBUF_ARCH_64_BIT 1
+#elif defined(__GNUC__)
+# if (((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)) || (__GNUC__ > 4))
+// We fallback to the generic Clang/GCC >= 4.7 implementation in atomicops.h
+# elif defined(__clang__)
+#  if !__has_extension(c_atomic)
+GOOGLE_PROTOBUF_PLATFORM_ERROR
+#  endif
+// We fallback to the generic Clang/GCC >= 4.7 implementation in atomicops.h
+# endif
+# if __LP64__
+#  define GOOGLE_PROTOBUF_ARCH_64_BIT 1
+# else
+#  define GOOGLE_PROTOBUF_ARCH_32_BIT 1
+# endif
 #else
-#error Host architecture was not detected as supported by protobuf
+GOOGLE_PROTOBUF_PLATFORM_ERROR
 #endif
 
 #if defined(__APPLE__)
 #define GOOGLE_PROTOBUF_OS_APPLE
+#include <TargetConditionals.h>
+#if TARGET_OS_IPHONE
+#define GOOGLE_PROTOBUF_OS_IPHONE
+#endif
+#elif defined(__EMSCRIPTEN__)
+#define GOOGLE_PROTOBUF_OS_EMSCRIPTEN
 #elif defined(__native_client__)
 #define GOOGLE_PROTOBUF_OS_NACL
+#elif defined(sun)
+#define GOOGLE_PROTOBUF_OS_SOLARIS
+#elif defined(_AIX)
+#define GOOGLE_PROTOBUF_OS_AIX
+#elif defined(__ANDROID__)
+#define GOOGLE_PROTOBUF_OS_ANDROID
+#endif
+
+#undef GOOGLE_PROTOBUF_PLATFORM_ERROR
+
+#if defined(GOOGLE_PROTOBUF_OS_ANDROID) || defined(GOOGLE_PROTOBUF_OS_APPLE)
+// Android ndk does not support the __thread keyword very well yet. Here
+// we use pthread_key_create()/pthread_getspecific()/... methods for
+// TLS support on android.
+// Apple Clang also does not support the __thread keyword.
+#define GOOGLE_PROTOBUF_NO_THREADLOCAL
 #endif
 
 #endif  // GOOGLE_PROTOBUF_PLATFORM_MACROS_H_