Export of internal Abseil changes.

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5da9755667df37e38ccaf6938c9f408e294110bb by Shaindel Schwartz <shaindel@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 232942734

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b6fb275769c66fdd2bd92b119198c59e9a7dd737 by Samuel Benzaquen <sbenza@google.com>:

Fix integral underflow when from-arg width is INT_MIN.

PiperOrigin-RevId: 232888037

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4135dbba4a26c4642277fc2a7e2a833d593daa1c by Abseil Team <absl-team@google.com>:

Add the insert_return_type alias to raw_hash_set.

PiperOrigin-RevId: 232683892

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0b120b7d3693800bbb886f6fc607ae54a9338cb1 by Abseil Team <absl-team@google.com>:

Macros to detect and disabled SafeStack
https://clang.llvm.org/docs/SafeStack.html

PiperOrigin-RevId: 232680114

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a77b3fb533a9e37966d1d6ef5ccd09c73fff2ca1 by Abseil Team <absl-team@google.com>:

Avoid potential red zone clobber

Pushing on the stack on x86-64 may clobber local variables held below
%rsp in the red zone. Avoid this by using lea on x86-64.

PiperOrigin-RevId: 232592478

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bf326a0eefa92f4e704287563df0c5a5b1873b6d by Eric Fiselier <ericwf@google.com>:

Add additional tests for AbslHashValue.

PiperOrigin-RevId: 232344325

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816e4f98fd7632c944c779db87b7dac4e138afcf by Eric Fiselier <ericwf@google.com>:

Avoid upcoming GCC 9.0 warnings about base class init.

Currently, in trunk, GCC has a new warning under -Wextra
that diagnoses when a derived class fails to explicitly
initialize the base class in a constructor initializer list.

This patch avoids this warning.

PiperOrigin-RevId: 232327626

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779c0f44b3c2b7a04d4bdf978641eb8180515bf6 by Eric Fiselier <ericwf@google.com>:

Guard against C++2a char8_t change.

PiperOrigin-RevId: 232326178

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41e5395b85bbbfb5bf418cc21b04ad4ccb15a284 by Eric Fiselier <ericwf@google.com>:

Avoid Clang Warning

PiperOrigin-RevId: 232138866
GitOrigin-RevId: 5da9755667df37e38ccaf6938c9f408e294110bb
Change-Id: I49ee4f58db177b81b039d7d949f671c97c5a7933

absl/strings/internal/str_format/bind.cc

@@ -53,7 +53,8 @@ inline bool ArgContext::Bind(const UnboundConversion* unbound,
         // "A negative field width is taken as a '-' flag followed by a
         // positive field width."
         force_left = true;
-        width = -width;
+        // Make sure we don't overflow the width when negating it.
+        width = -std::max(width, -std::numeric_limits<int>::max());
       }
     }
 

absl/strings/internal/str_format/bind_test.cc

@@ -1,6 +1,7 @@
 #include "absl/strings/internal/str_format/bind.h"
 
 #include <string.h>
+#include <limits>
 
 #include "gtest/gtest.h"
 
@@ -91,6 +92,20 @@ TEST_F(FormatBindTest, BindSingle) {
   }
 }
 
+TEST_F(FormatBindTest, WidthUnderflowRegression) {
+  UnboundConversion props;
+  BoundConversion bound;
+  int next = 0;
+  const int args_i[] = {std::numeric_limits<int>::min(), 17};
+  const FormatArgImpl args[] = {FormatArgImpl(args_i[0]),
+                                FormatArgImpl(args_i[1])};
+  ASSERT_TRUE(Extract("*d", &props, &next));
+  ASSERT_TRUE(BindWithPack(&props, args, &bound));
+
+  EXPECT_EQ(bound.width(), std::numeric_limits<int>::max());
+  EXPECT_EQ(bound.arg(), args + 1);
+}
+
 TEST_F(FormatBindTest, FormatPack) {
   struct Expectation {
     int line;

absl/strings/internal/utf8_test.cc

@@ -22,6 +22,11 @@
 
 namespace {
 
+#if !defined(__cpp_char8_t)
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wc++2a-compat"
+#endif
 TEST(EncodeUTF8Char, BasicFunction) {
   std::pair<char32_t, std::string> tests[] = {{0x0030, u8"\u0030"},
                                          {0x00A3, u8"\u00A3"},
@@ -53,5 +58,9 @@ TEST(EncodeUTF8Char, BasicFunction) {
   EXPECT_LE(absl::strings_internal::EncodeUTF8Char(buf2, -1),
             absl::strings_internal::kMaxEncodedUTF8Size);
 }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+#endif  // !defined(__cpp_char8_t)
 
 }  // namespace

absl/strings/str_split_test.cc

@@ -647,6 +647,11 @@ TEST(Split, StringDelimiter) {
   }
 }
 
+#if !defined(__cpp_char8_t)
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wc++2a-compat"
+#endif
 TEST(Split, UTF8) {
   // Tests splitting utf8 strings and utf8 delimiters.
   std::string utf8_string = u8"\u03BA\u1F79\u03C3\u03BC\u03B5";
@@ -673,6 +678,10 @@ TEST(Split, UTF8) {
     EXPECT_THAT(v, ElementsAre("Foo", u8"h\u00E4llo", u8"th\u4E1Ere"));
   }
 }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+#endif  // !defined(__cpp_char8_t)
 
 TEST(Split, EmptyStringDelimiter) {
   {