Export of internal Abseil changes

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20405fc394419d434d3ea09b2e62e4edcb282421 by Christian Blichmann <cblichmann@google.com>:

Include `status` subdirectory in main `CMakeLists.txt`

PiperOrigin-RevId: 297125966

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101087af9689612bdda679ee0869e5cde4472244 by Matt Kulukundis <kfm@google.com>:

Fix typo

PiperOrigin-RevId: 296991360

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55ff5bc6970d46214c0459d3a7a23973c7dc69b9 by Andy Getzendanner <durandal@google.com>:

Extract logging's ErrnoSaver to absl::base_internal and use it in a couple other places.

PiperOrigin-RevId: 296969168

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b7cd7550297d53766576f751436617200c65831b by Abseil Team <absl-team@google.com>:

Internal change

PiperOrigin-RevId: 296951474

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8c04c73fc53f9a09c3e2400812b931157f35fe07 by Andy Soffer <asoffer@google.com>:

Auto-generate list of files in the DLL, and add new build targets to the DLL.

PiperOrigin-RevId: 296932061

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2f77829e196094f1addefd8ac2ac9e398c5b6100 by Andy Soffer <asoffer@google.com>:

Fix bug introduced by DLL where we couldn't build shared libraries on
non-windows platforms.

Fixes #623

PiperOrigin-RevId: 296919347

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b768163dbbff0c561b9dff0218a699e5e4fd33f3 by Abseil Team <absl-team@google.com>:

typo: microprosessor

PiperOrigin-RevId: 296904933

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b185da0dac44c91855373f0723df9242cbfb3db3 by Matthew Brown <matthewbr@google.com>:

Internal cleanup

PiperOrigin-RevId: 296509711
GitOrigin-RevId: 20405fc394419d434d3ea09b2e62e4edcb282421
Change-Id: I55c8eba6f353ceb337455ae144ab743ea21edbef

1 files changed, 43 insertions, 0 deletions

diff --git a/absl/base/internal/errno_saver.h b/absl/base/internal/errno_saver.h
new file mode 100644
index 000000000000..251de510fc93
--- /dev/null
+++ b/absl/base/internal/errno_saver.h
@@ -0,0 +1,43 @@
+// Copyright 2017 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_BASE_INTERNAL_ERRNO_SAVER_H_
+#define ABSL_BASE_INTERNAL_ERRNO_SAVER_H_
+
+#include <cerrno>
+
+#include "absl/base/config.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace base_internal {
+
+// `ErrnoSaver` captures the value of `errno` upon construction and restores it
+// upon deletion.  It is used in low-level code and must be super fast.  Do not
+// add instrumentation, even in debug modes.
+class ErrnoSaver {
+ public:
+  ErrnoSaver() : saved_errno_(errno) {}
+  ~ErrnoSaver() { errno = saved_errno_; }
+  int operator()() const { return saved_errno_; }
+
+ private:
+  const int saved_errno_;
+};
+
+}  // namespace base_internal
+ABSL_NAMESPACE_END
+}  // namespace absl
+
+#endif  // ABSL_BASE_INTERNAL_ERRNO_SAVER_H_