Export of internal Abseil changes.

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5755b40f6025f3ca126070fc68adb8fde9a7f01b by Abseil Team <absl-team@google.com>:

Fix -Wextra-semi error.

PiperOrigin-RevId: 243215850

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3b6b6e18df9fbd233943cae460f0063f4efaa7c7 by Eric Fiselier <ericwf@google.com>:

Internal Change.

PiperOrigin-RevId: 243152671

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82eef03f246009c806c25607c5682547cb4ad21e by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 243151861

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c14e6340fca7070634e0ecfdf97833d930dd0e5d by Samuel Benzaquen <sbenza@google.com>:

Internal change

PiperOrigin-RevId: 243123590

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9abb7a6b22457c0aa72d72b3b9392efd226d302a by Andy Getzendanner <durandal@google.com>:

Implement operator<<(std::ostream &, absl::LogSeverity) so that absl::LogSeverity values can be streamed.

PiperOrigin-RevId: 243117646
GitOrigin-RevId: 5755b40f6025f3ca126070fc68adb8fde9a7f01b
Change-Id: I7ea607d8a4e803ad15a3090139271f58ad4173a3

absl/base/BUILD.bazel

@@ -135,6 +135,7 @@ cc_library(
         "internal/sysinfo.cc",
         "internal/thread_identity.cc",
         "internal/unscaledcycleclock.cc",
+        "log_severity.cc",
     ],
     hdrs = [
         "call_once.h",
@@ -162,6 +163,7 @@ cc_library(
         ":core_headers",
         ":dynamic_annotations",
         ":spinlock_wait",
+        "//absl/meta:type_traits",
     ],
 )
 
@@ -523,3 +525,15 @@ cc_test(
         "@com_google_googletest//:gtest_main",
     ],
 )
+
+cc_test(
+    name = "log_severity_test",
+    size = "small",
+    srcs = ["log_severity_test.cc"],
+    copts = ABSL_TEST_COPTS,
+    linkopts = ABSL_DEFAULT_LINKOPTS,
+    deps = [
+        ":base",
+        "@com_google_googletest//:gtest_main",
+    ],
+)