Export of internal Abseil changes.

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7fa1107161a03dac53fb84c2b06d8092616c7b13 by Abseil Team <absl-team@google.com>:

Harden the generic stacktrace implementation for use during early program execution

PiperOrigin-RevId: 226375950

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079f9969329f5eb66f647dd3c44b17541b1bf217 by Matt Kulukundis <kfm@google.com>:

Workaround platforms that have over-aggressive warnings on -Wexit-time-destructors

PiperOrigin-RevId: 226362948

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1447943f509be681ca5495add0162c750ef237f1 by Matt Kulukundis <kfm@google.com>:

Switch from 64 to size_t atomics so they work on embedded platforms that do not
have 64 bit atomics.

PiperOrigin-RevId: 226210704

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d14d49837ae2bcde74051e0c79c18ee0f43866b9 by Tom Manshreck <shreck@google.com>:

Develop initial documentation for API breaking changes process:

PiperOrigin-RevId: 226210021

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7ea3d7fe0e86979dab83a5fc9cc3bf1d6cb3bd53 by Abseil Team <absl-team@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 226195522

--
7de873e880d7f016a4fa1e08d626f0535cc470af by Abseil Team <absl-team@google.com>:

Make Abseil LICENSE files newline terminated, with a single
trailing blank line.  Also remove line-ending whitespace.

PiperOrigin-RevId: 226182949

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7d00643fadfad7f0d992c68bd9d2ed2e5bc960b0 by Matt Kulukundis <kfm@google.com>:

Internal cleanup

PiperOrigin-RevId: 226045282

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c4a0a11c0ce2875271191e477f3d36eaaeca4613 by Matt Kulukundis <kfm@google.com>:

Internal cleanup

PiperOrigin-RevId: 226038273

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8ee4ebbb1ae5cda119e436e5ff7e3aa966608c10 by Matt Kulukundis <kfm@google.com>:

Adds a global sampler which tracks a fraction of live tables for collecting
telemetry data.

PiperOrigin-RevId: 226032080

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d576446f050518cd1b0ae447d682d8552f0e7e30 by Mark Barolak <mbar@google.com>:

Replace an internal CaseEqual function with calls to the identical absl::EqualsIgnoreCase.  This closes out a rather old TODO.

PiperOrigin-RevId: 226024779

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6b23f1ee028a5ffa608c920424f1220a117a8f3d by Abseil Team <absl-team@google.com>:

Add December 2018 LTS branch to list of LTS branches.

PiperOrigin-RevId: 226011333

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bb0833a43bdaef4c8c059b17bcd27ba9a085a114 by Mark Barolak <mbar@google.com>:

Explicitly state that when the SimpleAtoi family of functions encounter an error, the value of their output parameter is unspecified.

Also standardize the name of the output parameter to be `out`.

PiperOrigin-RevId: 225997035

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46c1876b1a248eabda7545daa61a74a4cdfe9077 by Abseil Team <absl-team@google.com>:

Remove deprecated CMake function absl_test, absl_library and absl_header_library

PiperOrigin-RevId: 225950041
GitOrigin-RevId: 7fa1107161a03dac53fb84c2b06d8092616c7b13
Change-Id: I2ca9d3aada9292614527d1339a7557494139b806

1 files changed, 17 insertions, 0 deletions

diff --git a/absl/UPGRADES.md b/absl/UPGRADES.md
new file mode 100644
index 000000000000..edbc4dc4dd32
--- /dev/null
+++ b/absl/UPGRADES.md
@@ -0,0 +1,17 @@
+# C++ Upgrade Tools
+
+Abseil may occassionally release API-breaking changes. As noted in our
+[Compatibility Guidelines][compatibility-guide], we will aim to provide a tool
+to do the work of effecting such API-breaking changes, when absolutely
+necessary.
+
+These tools will be listed on the [C++ Upgrade Tools][upgrade-tools] guide on
+http://abseil.io.
+
+For more information, the [C++ Automated Upgrade Guide][api-upgrades-guide]
+outlines this process.
+
+[compatibility-guide]: https://abseil.io/about/compatibility
+[api-upgrades-guide]: https://abseil.io/docs/cpp/tools/api-upgrades
+[upgrade-tools]: https://abseil.io/docs/cpp/tools/upgrades/
+