Export of internal Abseil changes

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730bb88bee556aa11fa19aa33e1434cb6fa78985 by Evan Brown <ezb@google.com>:

Support missing allocator-related constructors in b-tree. See [reference](https://en.cppreference.com/w/cpp/container/set/set).

Also use allocator_traits::select_on_container_copy_construction() to get allocator for copy construction.

PiperOrigin-RevId: 339058322

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b6cc121689ae3e452d1db2d66122cb198d25142b by Derek Mauro <dmauro@google.com>:

Fix more sign-compare warnings

PiperOrigin-RevId: 339057920

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0e2c62da1dcaf6529abab952bdcc96c6de2d9506 by Abseil Team <absl-team@google.com>:

Add missing <limits> include

PiperOrigin-RevId: 339054753

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d5a9ec2d1e40fe6359e720942e4955009ee415ec by Derek Mauro <dmauro@google.com>:

Stop disabling sign-compare warnings for non-test targets.
Our users complain about these.

This does not catch issues in header-only libraries (like btree.h)
but we may work on those in the future

PiperOrigin-RevId: 338967089

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0c062c542a4c61ea0f65d25811827c0858e3adde by Abseil Team <absl-team@google.com>:

Improve cache-locality for ThreadIdentity and PerThreadSynch.

This is a change based on an observation in RPC benchmarks that shows
significant cycles being spent in waking up a thread, 99.8% of which
was on cache misses. Investigating this a bit more, it turns out to
be due to sharing the cache line with the waiter state.

To fix this issue, the following changes are introduced:
- Reorder fields in PerThreadSync so that it fits in a single cache line
  The size of this structure was 80 bytes before this change.
  Note: Manually inspected all booleans to make sure they are not modified by
        multiple threads concurrently.

PiperOrigin-RevId: 338852058

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a90d6f2b2346385017e32dd8ae1b5ca691a5863f by Derek Mauro <dmauro@google.com>:

Delete GCC 4.9 test script. It is no longer supported

PiperOrigin-RevId: 338779452

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7274008d4757e88869110be9db39d03d911ae2b5 by Abseil Team <absl-team@google.com>:

Fix the usage example in which SetFlag should take a pointer.

PiperOrigin-RevId: 338744529
GitOrigin-RevId: 730bb88bee556aa11fa19aa33e1434cb6fa78985
Change-Id: Iff99594c4022e60e482a392d334b376c7ae8883e

1 files changed, 1 insertions, 0 deletions

diff --git a/absl/synchronization/internal/graphcycles.cc b/absl/synchronization/internal/graphcycles.cc
index 19f9aab5..27fec216 100644
--- a/absl/synchronization/internal/graphcycles.cc
+++ b/absl/synchronization/internal/graphcycles.cc
@@ -37,6 +37,7 @@
 
 #include <algorithm>
 #include <array>
+#include <limits>
 #include "absl/base/internal/hide_ptr.h"
 #include "absl/base/internal/raw_logging.h"
 #include "absl/base/internal/spinlock.h"