Export of internal Abseil changes

--
9beb68204986a015c9cb065b9fae4f9a8879a788 by Abseil Team <absl-team@google.com>:

Move Base64EscapeInternal and CalculateBase64EscapedLenInternal to an internal header.

PiperOrigin-RevId: 288917378

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90acfbe03b3f9f6de3ffa49c39343dfaa2c5d38c by Greg Falcon <gfalcon@google.com>:

Update macos CI script to support the ALTERNATE_OPTIONS environment variable.

PiperOrigin-RevId: 288913564

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f1572e870678cdcda6b48cb39780d1ad984e4c1b by Derek Mauro <dmauro@google.com>:

Makes absl::NullSafeStringView constexpr
Fixes https://github.com/abseil/abseil-cpp/issues/583

PiperOrigin-RevId: 288906940

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d28a8471e32c10caa64bfffe6d6d4d0a8d144013 by Abseil Team <absl-team@google.com>:

absl::GetFlag is lock free for small trivially copyable types.

PiperOrigin-RevId: 288768172

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2643b8ed1a1dc836b38ab9e46538a1af129ffd67 by Gennadiy Rozental <rogeeff@google.com>:

Eliminate call to callback from flag initialization.

We do not need to have this invocation inside FlagImpl::Init since SetCallback performs invocation anyways. Calling InitCallback from inside of Init complicates separation of value initialization from data guard initialization, which is about to happen.

PiperOrigin-RevId: 288732526

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22caa880b7a4cb6da34e16a2e064a473c99e880b by Abseil Team <absl-team@google.com>:

Fix the documentation on how to create a null string_view.

PiperOrigin-RevId: 288727968

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10727c5cadc561837141176f4c9b9717cec9233a by Greg Falcon <gfalcon@google.com>:

Change CI scripts for gcc to use the ALTERNATE_OPTIONS file as well.

PiperOrigin-RevId: 288718855

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5d1e2dd6c7fb12af8aa4337a0f61872f5f0c5992 by Greg Falcon <gfalcon@google.com>:

Add an option for using inline namespaces in Abseil.

PiperOrigin-RevId: 288614491
GitOrigin-RevId: 9beb68204986a015c9cb065b9fae4f9a8879a788
Change-Id: If9acd46301e3df8cb231b4c16f7ed651bf4fb3c3

3 files changed, 25 insertions, 14 deletions

diff --git a/ci/absl_types_options.h b/ci/absl_types_options.h
index 8f8ed34..307fde6 100644
--- a/ci/absl_types_options.h
+++ b/ci/absl_types_options.h
@@ -22,6 +22,7 @@
 #define ABSL_OPTION_USE_STD_OPTIONAL 0
 #define ABSL_OPTION_USE_STD_STRING_VIEW 0
 #define ABSL_OPTION_USE_STD_VARIANT 0
-
+#define ABSL_OPTION_USE_INLINE_NAMESPACE 1
+#define ABSL_OPTION_INLINE_NAMESPACE_NAME ns
 
 #endif  // ABSL_BASE_OPTIONS_H_
diff --git a/ci/linux_gcc-latest_libstdcxx_bazel.sh b/ci/linux_gcc-latest_libstdcxx_bazel.sh
index 2d41d51..5964703 100755
--- a/ci/linux_gcc-latest_libstdcxx_bazel.sh
+++ b/ci/linux_gcc-latest_libstdcxx_bazel.sh
@@ -55,7 +55,8 @@ for std in ${STD}; do
     for exceptions_mode in ${EXCEPTIONS_MODE}; do
       echo "--------------------------------------------------------------------"
       time docker run \
-        --volume="${ABSEIL_ROOT}:/abseil-cpp:ro" \
+        --volume="${ABSEIL_ROOT}:/abseil-cpp-ro:ro" \
+        --tmpfs=/abseil-cpp \
         --workdir=/abseil-cpp \
         --cap-add=SYS_PTRACE \
         --rm \
@@ -63,18 +64,23 @@ for std in ${STD}; do
         -e BAZEL_CXXOPTS="-std=${std}" \
         ${DOCKER_EXTRA_ARGS:-} \
         ${DOCKER_CONTAINER} \
-        /usr/local/bin/bazel test ... \
-          --compilation_mode="${compilation_mode}" \
-          --copt="${exceptions_mode}" \
-          --copt=-Werror \
-          --define="absl=1" \
-          --keep_going \
-          --show_timestamps \
-          --test_env="GTEST_INSTALL_FAILURE_SIGNAL_HANDLER=1" \
-          --test_env="TZDIR=/abseil-cpp/absl/time/internal/cctz/testdata/zoneinfo" \
-          --test_output=errors \
-          --test_tag_filters=-benchmark \
-          ${BAZEL_EXTRA_ARGS:-}
+        /bin/sh -c "
+          cp -r /abseil-cpp-ro/* /abseil-cpp/
+          if [ -n \"${ALTERNATE_OPTIONS:-}\" ]; then
+            cp ${ALTERNATE_OPTIONS:-} absl/base/options.h || exit 1
+          fi
+          /usr/local/bin/bazel test ... \
+            --compilation_mode=\"${compilation_mode}\" \
+            --copt=\"${exceptions_mode}\" \
+            --copt=-Werror \
+            --define=\"absl=1\" \
+            --keep_going \
+            --show_timestamps \
+            --test_env=\"GTEST_INSTALL_FAILURE_SIGNAL_HANDLER=1\" \
+            --test_env=\"TZDIR=/abseil-cpp/absl/time/internal/cctz/testdata/zoneinfo\" \
+            --test_output=errors \
+            --test_tag_filters=-benchmark \
+            ${BAZEL_EXTRA_ARGS:-}"
     done
   done
 done
diff --git a/ci/macos_xcode_bazel.sh b/ci/macos_xcode_bazel.sh
index 3cf1be4..f5f2d75 100755
--- a/ci/macos_xcode_bazel.sh
+++ b/ci/macos_xcode_bazel.sh
@@ -41,6 +41,10 @@ echo "---------------"
 
 cd ${ABSEIL_ROOT}
 
+if [ -n "${ALTERNATE_OPTIONS:-}" ]; then
+  cp ${ALTERNATE_OPTIONS:-} absl/base/options.h || exit 1
+fi
+
 ${BAZEL_BIN} test ... \
   --copt=-Werror \
   --keep_going \