Export of internal Abseil changes

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3a871e2cd854a46770a9416189953b2b38980bcf by Andy Getzendanner <durandal@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 280660534

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f5a155fb056dcf68b089c21aebb5bf5159dc0eb3 by Tom Manshreck <shreck@google.com>:

Nit: fix format of algorithm.h comments

PiperOrigin-RevId: 280474139

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08b117a18353c0daf51b33b45100e5a007e5ab0c by Abseil Team <absl-team@google.com>:

Allow absl::Notification::HasBeenNotified to be inlined.

PiperOrigin-RevId: 280453271

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26d33dd2bad72945f1987f7b2669dbec3a6247e6 by Derek Mauro <dmauro@google.com>:

Fix unused variable warnings on Windows

PiperOrigin-RevId: 280324417

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907e9b23029be683af3b443bafd6a577a595922f by Abseil Team <absl-team@google.com>:

PeriodicSampler implementation (for internal-use only)

PiperOrigin-RevId: 280257168
GitOrigin-RevId: 3a871e2cd854a46770a9416189953b2b38980bcf
Change-Id: I6e2978cae22a6adc41c0577e5c21355e9db7c8f5

1 files changed, 8 insertions, 3 deletions

diff --git a/absl/algorithm/algorithm.h b/absl/algorithm/algorithm.h
index bb90215d..771228a0 100644
--- a/absl/algorithm/algorithm.h
+++ b/absl/algorithm/algorithm.h
@@ -84,6 +84,8 @@ It RotateImpl(It first, It middle, It last, std::false_type) {
 
 }  // namespace algorithm_internal
 
+// equal()
+//
 // Compares the equality of two ranges specified by pairs of iterators, using
 // the given predicate, returning true iff for each corresponding iterator i1
 // and i2 in the first and second range respectively, pred(*i1, *i2) == true
@@ -104,8 +106,8 @@ bool equal(InputIter1 first1, InputIter1 last1, InputIter2 first2,
       typename std::iterator_traits<InputIter2>::iterator_category{});
 }
 
-// Performs comparison of two ranges specified by pairs of iterators using
-// operator==.
+// Overload of equal() that performs comparison of two ranges specified by pairs
+// of iterators using operator==.
 template <typename InputIter1, typename InputIter2>
 bool equal(InputIter1 first1, InputIter1 last1, InputIter2 first2,
            InputIter2 last2) {
@@ -113,6 +115,8 @@ bool equal(InputIter1 first1, InputIter1 last1, InputIter2 first2,
                      algorithm_internal::EqualTo{});
 }
 
+// linear_search()
+//
 // Performs a linear search for `value` using the iterator `first` up to
 // but not including `last`, returning true if [`first`, `last`) contains an
 // element equal to `value`.
@@ -126,6 +130,8 @@ bool linear_search(InputIterator first, InputIterator last,
   return std::find(first, last, value) != last;
 }
 
+// rotate()
+//
 // Performs a left rotation on a range of elements (`first`, `last`) such that
 // `middle` is now the first element. `rotate()` returns an iterator pointing to
 // the first element before rotation. This function is exactly the same as
@@ -135,7 +141,6 @@ bool linear_search(InputIterator first, InputIterator last,
 // The complexity of this algorithm is the same as that of `std::rotate`, but if
 // `ForwardIterator` is not a random-access iterator, then `absl::rotate`
 // performs an additional pass over the range to construct the return value.
-
 template <typename ForwardIterator>
 ForwardIterator rotate(ForwardIterator first, ForwardIterator middle,
                        ForwardIterator last) {