Add clang-cl build

PiperOrigin-RevId: 520955097
Change-Id: I50a19305aed2b60dea0293b1a2106673e4cb7756

ci/windows_clangcl_bazel.bat

+:: Copyright 2023 The Abseil Authors
+::
+:: Licensed under the Apache License, Version 2.0 (the "License");
+:: you may not use this file except in compliance with the License.
+:: You may obtain a copy of the License at
+::
+::     https://www.apache.org/licenses/LICENSE-2.0
+::
+:: Unless required by applicable law or agreed to in writing, software
+:: distributed under the License is distributed on an "AS IS" BASIS,
+:: WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+:: See the License for the specific language governing permissions and
+:: limitations under the License.
+
+SETLOCAL ENABLEDELAYEDEXPANSION
+
+:: Set LLVM directory.
+SET BAZEL_LLVM=C:\Program Files\LLVM
+
+:: Change directory to the root of the project.
+CD %~dp0\..
+if %errorlevel% neq 0 EXIT /B 1
+
+:: Set the standard version, [c++14|c++17|c++20|c++latest]
+:: https://msdn.microsoft.com/en-us/library/mt490614.aspx
+:: The default is c++14 if not set on command line.
+IF "%STD%"=="" SET STD=c++14
+
+:: Set the compilation_mode (fastbuild|opt|dbg)
+:: https://docs.bazel.build/versions/master/user-manual.html#flag--compilation_mode
+:: The default is fastbuild
+IF "%COMPILATION_MODE%"=="" SET COMPILATION_MODE=fastbuild
+
+:: Copy the alternate option file, if specified.
+IF NOT "%ALTERNATE_OPTIONS%"=="" copy %ALTERNATE_OPTIONS% absl\base\options.h
+
+:: To upgrade Bazel, first download a new binary from
+:: https://github.com/bazelbuild/bazel/releases and copy it to
+:: /google/data/rw/teams/absl/kokoro/windows.
+::
+:: TODO(absl-team): Remove -Wno-microsoft-cast
+%KOKORO_GFILE_DIR%\bazel-5.1.1-windows-x86_64.exe ^
+  test ... ^
+  --compilation_mode=%COMPILATION_MODE% ^
+  --compiler=clang-cl ^
+  --copt=/std:%STD% ^
+  --copt=/WX ^
+  --copt=-Wno-microsoft-cast ^
+  --define=absl=1 ^
+  --distdir=%KOKORO_GFILE_DIR%\distdir ^
+  --features=external_include_paths ^
+  --keep_going ^
+  --test_env="GTEST_INSTALL_FAILURE_SIGNAL_HANDLER=1" ^
+  --test_env=TZDIR="%CD%\absl\time\internal\cctz\testdata\zoneinfo" ^
+  --test_output=errors ^
+  --test_tag_filters=-benchmark
+
+if %errorlevel% neq 0 EXIT /B 1
+EXIT /B 0