Update to the Clang v20.1.7 version of the main

[ktf]

No description provided.

[alibuild]

Error while checking build/o2codechecker/o2 for 85f3dd5 at 2025-08-12 09:38:

## sw/BUILD/o2codechecker-latest/log
CMake Error at /sw/slc9_x86-64/Clang/v18.1.8-21/lib/cmake/llvm/AddLLVM.cmake:596 (add_library):
CMake Error at /sw/slc9_x86-64/Clang/v18.1.8-21/lib/cmake/llvm/AddLLVM.cmake:720 (target_link_libraries):

Full log here.

[alibuild]

Error while checking build/o2codechecker/o2 for afd6c48 at 2025-08-27 09:56:

## sw/BUILD/o2codechecker-latest/log
/sw/SOURCES/o2codechecker/build_o2codechecker_o2-slc9_x86-64/0/tool/ClangTidyMain.cpp:386:18: error: 'struct clang::tidy::ClangTidyOptions' has no member named 'ExcludeHeaderFilterRegex'; did you mean 'HeaderFilterRegex'?
/sw/SOURCES/o2codechecker/build_o2codechecker_o2-slc9_x86-64/0/tool/ClangTidyMain.cpp:402:21: error: 'struct clang::tidy::ClangTidyOptions' has no member named 'ExcludeHeaderFilterRegex'; did you mean 'HeaderFilterRegex'?
/sw/SOURCES/o2codechecker/build_o2codechecker_o2-slc9_x86-64/0/tool/ClangTidyMain.cpp:492:33: error: 'class clang::tidy::GlobList' has no member named 'getItems'; did you mean 'llvm::SmallVector<clang::tidy::GlobList::GlobListItem, 0> clang::tidy::GlobList::Items'? (not accessible from this context)
/sw/SOURCES/o2codechecker/build_o2codechecker_o2-slc9_x86-64/0/tool/ClangTidyMain.cpp:496:53: error: 'Item' is not captured
/sw/SOURCES/o2codechecker/build_o2codechecker_o2-slc9_x86-64/0/tool/ClangTidyMain.cpp:672:5: error: 'ChecksAndOptions' was not declared in this scope; did you mean 'NamesAndOptions'?
/sw/SOURCES/o2codechecker/build_o2codechecker_o2-slc9_x86-64/0/tool/ClangTidyMain.cpp:677:36: error: 'Valid' was not declared in this scope
/sw/SOURCES/o2codechecker/build_o2codechecker_o2-slc9_x86-64/0/tool/ClangTidyMain.cpp:682:35: error: 'Valid' was not declared in this scope
make[2]: *** [tool/CMakeFiles/clangTidyMainO2.dir/build.make:79: tool/CMakeFiles/clangTidyMainO2.dir/ClangTidyMain.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:388: tool/CMakeFiles/clangTidyMainO2.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:146: all] Error 2

Full log here.

[ktf]

@sawenzel any objections to this? Basically the new versions of clang seem to have proper plugin management.

[ktf]

Discussed offline. Merging.