[clang] [llvm] Add macro to suppress -Wunnecessary-virtual-specifier (PR #139614)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-key-instructions` running on `sie-linux-worker5` while building `clang,llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/208/builds/1347

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

```
Step 5 (build-unified-tree) failure: build (failure)
0.069 [6576/10/1] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/ABIBreak.cpp.o
0.576 [6575/10/2] Building CXX object lib/Demangle/CMakeFiles/LLVMDemangle.dir/Demangle.cpp.o
0.692 [6574/10/3] Building CXX object lib/Demangle/CMakeFiles/LLVMDemangle.dir/DLangDemangle.cpp.o
1.258 [6573/10/4] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/APInt.cpp.o
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/APInt.cpp.o 
/opt/ccache/bin/g++ -DEXPERIMENTAL_KEY_INSTRUCTIONS -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/buildbot/buildbot-root/llvm-ki/build/lib/Support -I/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support -I/home/buildbot/buildbot-root/llvm-ki/build/include -I/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -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-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -UNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/APInt.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/APInt.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/APInt.cpp.o -c /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support/APInt.cpp
In file included from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/ADT/APInt.h:18,
                 from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support/APInt.cpp:14:
/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/Support/Compiler.h:719:40: error: missing binary operator before token "("
  719 | #if defined(__clang__) && __has_warning("-Wunnecessary-virtual-specifier")
      |                                        ^
1.308 [6573/9/5] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/APFixedPoint.cpp.o
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/APFixedPoint.cpp.o 
/opt/ccache/bin/g++ -DEXPERIMENTAL_KEY_INSTRUCTIONS -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/buildbot/buildbot-root/llvm-ki/build/lib/Support -I/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support -I/home/buildbot/buildbot-root/llvm-ki/build/include -I/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -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-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -UNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/APFixedPoint.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/APFixedPoint.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/APFixedPoint.cpp.o -c /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support/APFixedPoint.cpp
In file included from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/ADT/APInt.h:18,
                 from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/ADT/APSInt.h:18,
                 from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/ADT/APFixedPoint.h:19,
                 from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support/APFixedPoint.cpp:14:
/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/Support/Compiler.h:719:40: error: missing binary operator before token "("
  719 | #if defined(__clang__) && __has_warning("-Wunnecessary-virtual-specifier")
      |                                        ^
1.332 [6573/8/6] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/APSInt.cpp.o
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/APSInt.cpp.o 
/opt/ccache/bin/g++ -DEXPERIMENTAL_KEY_INSTRUCTIONS -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/buildbot/buildbot-root/llvm-ki/build/lib/Support -I/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support -I/home/buildbot/buildbot-root/llvm-ki/build/include -I/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -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-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -UNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/APSInt.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/APSInt.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/APSInt.cpp.o -c /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support/APSInt.cpp
In file included from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/ADT/APInt.h:18,
                 from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/ADT/APSInt.h:18,
                 from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support/APSInt.cpp:14:
/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/Support/Compiler.h:719:40: error: missing binary operator before token "("
  719 | #if defined(__clang__) && __has_warning("-Wunnecessary-virtual-specifier")
      |                                        ^
1.479 [6573/7/7] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/ARMBuildAttributes.cpp.o
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/ARMBuildAttributes.cpp.o 
/opt/ccache/bin/g++ -DEXPERIMENTAL_KEY_INSTRUCTIONS -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/buildbot/buildbot-root/llvm-ki/build/lib/Support -I/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support -I/home/buildbot/buildbot-root/llvm-ki/build/include -I/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -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-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -UNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/ARMBuildAttributes.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/ARMBuildAttributes.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/ARMBuildAttributes.cpp.o -c /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support/ARMBuildAttributes.cpp
In file included from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/Support/ARMBuildAttributes.h:21,
                 from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support/ARMBuildAttributes.cpp:9:
/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/Support/Compiler.h:719:40: error: missing binary operator before token "("
  719 | #if defined(__clang__) && __has_warning("-Wunnecessary-virtual-specifier")
      |                                        ^
1.496 [6573/6/8] Building CXX object lib/Demangle/CMakeFiles/LLVMDemangle.dir/MicrosoftDemangleNodes.cpp.o
1.509 [6573/5/9] Building CXX object lib/Demangle/CMakeFiles/LLVMDemangle.dir/RustDemangle.cpp.o
1.562 [6573/4/10] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/APFloat.cpp.o
FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/APFloat.cpp.o 
/opt/ccache/bin/g++ -DEXPERIMENTAL_KEY_INSTRUCTIONS -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/buildbot/buildbot-root/llvm-ki/build/lib/Support -I/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support -I/home/buildbot/buildbot-root/llvm-ki/build/include -I/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -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-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -UNDEBUG -std=c++17  -fno-exceptions -funwind-tables -fno-rtti -MD -MT lib/Support/CMakeFiles/LLVMSupport.dir/APFloat.cpp.o -MF lib/Support/CMakeFiles/LLVMSupport.dir/APFloat.cpp.o.d -o lib/Support/CMakeFiles/LLVMSupport.dir/APFloat.cpp.o -c /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support/APFloat.cpp
In file included from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/ADT/APInt.h:18,
                 from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/ADT/APFloat.h:18,
                 from /home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/lib/Support/APFloat.cpp:14:
/home/buildbot/buildbot-root/llvm-ki/llvm-project/llvm/include/llvm/Support/Compiler.h:719:40: error: missing binary operator before token "("
  719 | #if defined(__clang__) && __has_warning("-Wunnecessary-virtual-specifier")
      |                                        ^
1.626 [6573/3/11] Building CXX object lib/Support/CMakeFiles/LLVMSupport.dir/AMDGPUMetadata.cpp.o

```

</details>

https://github.com/llvm/llvm-project/pull/139614