Adding Google benchmarking library.

third_party/google_benchmark/include/benchmark/macros.h

Index: third_party/google_benchmark/include/benchmark/macros.h
diff --git a/third_party/google_benchmark/include/benchmark/macros.h b/third_party/google_benchmark/include/benchmark/macros.h
new file mode 100644
index 0000000000000000000000000000000000000000..2466fd3fad06c5f8386170f3f568457d1e2600f3
--- /dev/null
+++ b/third_party/google_benchmark/include/benchmark/macros.h
@@ -0,0 +1,66 @@
+// Copyright 2015 Google Inc. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#ifndef BENCHMARK_MACROS_H_
+#define BENCHMARK_MACROS_H_
+
+#if __cplusplus >= 201103L
+#define BENCHMARK_HAS_CXX11
+#endif
+
+#ifndef BENCHMARK_HAS_CXX11
+#define BENCHMARK_DISALLOW_COPY_AND_ASSIGN(TypeName) \
+  TypeName(const TypeName&);                         \
+  TypeName& operator=(const TypeName&)
+#else
+#define BENCHMARK_DISALLOW_COPY_AND_ASSIGN(TypeName) \
+  TypeName(const TypeName&) = delete;                \
+  TypeName& operator=(const TypeName&) = delete
+#endif
+
+#if defined(__GNUC__)
+#define BENCHMARK_UNUSED __attribute__((unused))
+#define BENCHMARK_ALWAYS_INLINE __attribute__((always_inline))
+#define BENCHMARK_NOEXCEPT noexcept
+#define BENCHMARK_NOEXCEPT_OP(x) noexcept(x)
+#elif defined(_MSC_VER) && !defined(__clang__)
+#define BENCHMARK_UNUSED
+#define BENCHMARK_ALWAYS_INLINE __forceinline
+#if _MSC_VER >= 1900
+#define BENCHMARK_NOEXCEPT noexcept
+#define BENCHMARK_NOEXCEPT_OP(x) noexcept(x)
+#else
+#define BENCHMARK_NOEXCEPT
+#define BENCHMARK_NOEXCEPT_OP(x)
+#endif
+#define __func__ __FUNCTION__
+#else
+#define BENCHMARK_UNUSED
+#define BENCHMARK_ALWAYS_INLINE
+#define BENCHMARK_NOEXCEPT
+#define BENCHMARK_NOEXCEPT_OP(x)
+#endif
+
+#if defined(__GNUC__)
+#define BENCHMARK_BUILTIN_EXPECT(x, y) __builtin_expect(x, y)
+#define BENCHMARK_DEPRECATED_MSG(msg) __attribute__((deprecated(msg)))
+#else
+#define BENCHMARK_BUILTIN_EXPECT(x, y) x
+#define BENCHMARK_DEPRECATED_MSG(msg)
+#endif
+
+#if defined(__GNUC__) && !defined(__clang__)
+#define BENCHMARK_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
+#endif
+
+#endif  // BENCHMARK_MACROS_H_