Add 'third_party/abseil_cpp/' from commit '768eb2ca28'

git-subtree-dir: third_party/abseil_cpp
git-subtree-mainline: ffb2ae54be
git-subtree-split: 768eb2ca28

third_party/abseil_cpp/absl/flags/config.h

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+//
+//  Copyright 2019 The Abseil Authors.
+//
+// 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
+//
+//      https://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 ABSL_FLAGS_CONFIG_H_
+#define ABSL_FLAGS_CONFIG_H_
+
+// Determine if we should strip string literals from the Flag objects.
+// By default we strip string literals on mobile platforms.
+#if !defined(ABSL_FLAGS_STRIP_NAMES)
+
+#if defined(__ANDROID__)
+#define ABSL_FLAGS_STRIP_NAMES 1
+
+#elif defined(__APPLE__)
+#include <TargetConditionals.h>
+#if defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE
+#define ABSL_FLAGS_STRIP_NAMES 1
+#elif defined(TARGET_OS_EMBEDDED) && TARGET_OS_EMBEDDED
+#define ABSL_FLAGS_STRIP_NAMES 1
+#endif  // TARGET_OS_*
+#endif
+
+#endif  // !defined(ABSL_FLAGS_STRIP_NAMES)
+
+#if !defined(ABSL_FLAGS_STRIP_NAMES)
+// If ABSL_FLAGS_STRIP_NAMES wasn't set on the command line or above,
+// the default is not to strip.
+#define ABSL_FLAGS_STRIP_NAMES 0
+#endif
+
+#if !defined(ABSL_FLAGS_STRIP_HELP)
+// By default, if we strip names, we also strip help.
+#define ABSL_FLAGS_STRIP_HELP ABSL_FLAGS_STRIP_NAMES
+#endif
+
+// ABSL_FLAGS_INTERNAL_ATOMIC_DOUBLE_WORD macro is used for using atomics with
+// double words, e.g. absl::Duration.
+// For reasons in bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80878, modern
+// versions of GCC do not support cmpxchg16b instruction in standard atomics.
+#ifdef ABSL_FLAGS_INTERNAL_ATOMIC_DOUBLE_WORD
+#error "ABSL_FLAGS_INTERNAL_ATOMIC_DOUBLE_WORD should not be defined."
+#elif defined(__clang__) && defined(__x86_64__) && \
+    defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_16)
+#define ABSL_FLAGS_INTERNAL_ATOMIC_DOUBLE_WORD 1
+#endif
+
+// ABSL_FLAGS_INTERNAL_HAS_RTTI macro is used for selecting if we can use RTTI
+// for flag type identification.
+#ifdef ABSL_FLAGS_INTERNAL_HAS_RTTI
+#error ABSL_FLAGS_INTERNAL_HAS_RTTI cannot be directly set
+#elif !defined(__GNUC__) || defined(__GXX_RTTI)
+#define ABSL_FLAGS_INTERNAL_HAS_RTTI 1
+#endif  // !defined(__GNUC__) || defined(__GXX_RTTI)
+
+// These macros represent the "source of truth" for the list of supported
+// built-in types.
+#define ABSL_FLAGS_INTERNAL_BUILTIN_TYPES(A) \
+  A(bool, bool)                              \
+  A(short, short)                            \
+  A(unsigned short, unsigned_short)          \
+  A(int, int)                                \
+  A(unsigned int, unsigned_int)              \
+  A(long, long)                              \
+  A(unsigned long, unsigned_long)            \
+  A(long long, long_long)                    \
+  A(unsigned long long, unsigned_long_long)  \
+  A(double, double)                          \
+  A(float, float)
+
+#define ABSL_FLAGS_INTERNAL_SUPPORTED_TYPES(A) \
+  ABSL_FLAGS_INTERNAL_BUILTIN_TYPES(A)         \
+  A(std::string, std_string)                   \
+  A(std::vector<std::string>, std_vector_of_string)
+
+#endif  // ABSL_FLAGS_CONFIG_H_