[llvm] Remove dependence on <ciso646> (PR #73273)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-ppc64le-linux-test-suite` running on `ppc64le-clang-test-suite` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/95/builds/9402

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (build-unified-tree) failure: build (failure)
1.126 [4371/58/1] Generating VCSRevision.h
1.884 [4371/57/2] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/raw_socket_stream.cpp.o
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/raw_socket_stream.cpp.o 
ccache /usr/lib64/ccache/c++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/lib/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17 -UNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/raw_socket_stream.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/raw_socket_stream.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/raw_socket_stream.cpp.o -c /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support/raw_socket_stream.cpp
In file included from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/raw_socket_stream.h:17,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support/raw_socket_stream.cpp:14:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/Threading.h:22:10: fatal error: version: No such file or directory
 #include <version>
          ^~~~~~~~~
compilation terminated.
1.904 [4371/56/3] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/DynamicLibrary.cpp.o
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/DynamicLibrary.cpp.o 
ccache /usr/lib64/ccache/c++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/lib/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17 -UNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/DynamicLibrary.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/DynamicLibrary.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/DynamicLibrary.cpp.o -c /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support/DynamicLibrary.cpp
In file included from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/Mutex.h:16,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support/DynamicLibrary.cpp:18:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/Threading.h:22:10: fatal error: version: No such file or directory
 #include <version>
          ^~~~~~~~~
compilation terminated.
1.913 [4371/55/4] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/Timer.cpp.o
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/Timer.cpp.o 
ccache /usr/lib64/ccache/c++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/lib/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17 -UNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/Timer.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/Timer.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/Timer.cpp.o -c /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support/Timer.cpp
In file included from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/Mutex.h:16,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/Timer.h:15,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support/Timer.cpp:13:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/Threading.h:22:10: fatal error: version: No such file or directory
 #include <version>
          ^~~~~~~~~
compilation terminated.
1.914 [4371/54/5] Building CXX object tools/clang/utils/TableGen/CMakeFiles/clang-tblgen.dir/ClangASTPropertiesEmitter.cpp.o
FAILED: tools/clang/utils/TableGen/CMakeFiles/clang-tblgen.dir/ClangASTPropertiesEmitter.cpp.o 
ccache /usr/lib64/ccache/c++ -DCLANG_EXPORTS -DGTEST_HAS_RTTI=0 -DLLVM_BUILD_STATIC -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/tools/clang/utils/TableGen -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/clang/utils/TableGen -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/clang/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/tools/clang/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -fno-common -Woverloaded-virtual -fno-strict-aliasing -O3 -DNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -MD -MT tools/clang/utils/TableGen/CMakeFiles/clang-tblgen.dir/ClangASTPropertiesEmitter.cpp.o -MF tools/clang/utils/TableGen/CMakeFiles/clang-tblgen.dir/ClangASTPropertiesEmitter.cpp.o.d -o tools/clang/utils/TableGen/CMakeFiles/clang-tblgen.dir/ClangASTPropertiesEmitter.cpp.o -c /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/clang/utils/TableGen/ClangASTPropertiesEmitter.cpp
In file included from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/Mutex.h:16,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/Timer.h:15,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/TableGen/Record.h:28,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/clang/utils/TableGen/ASTTableGen.h:12,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/clang/utils/TableGen/ClangASTPropertiesEmitter.cpp:13:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/Threading.h:22:10: fatal error: version: No such file or directory
 #include <version>
          ^~~~~~~~~
compilation terminated.
1.914 [4371/53/6] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/ThreadPool.cpp.o
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/ThreadPool.cpp.o 
ccache /usr/lib64/ccache/c++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/lib/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/build/include -I/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17 -UNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/ThreadPool.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/ThreadPool.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/ThreadPool.cpp.o -c /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support/ThreadPool.cpp
In file included from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/RWMutex.h:17,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/ThreadPool.h:18,
                 from /home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/lib/Support/ThreadPool.cpp:13:
/home/buildbots/llvm-external-buildbots/workers/ppc64le-clang-test-suite/clang-ppc64le-test-suite/llvm-project/llvm/include/llvm/Support/Threading.h:22:10: fatal error: version: No such file or directory
 #include <version>
          ^~~~~~~~~

```

</details>

https://github.com/llvm/llvm-project/pull/73273