Dependencies which need to go in first:

• More preparation for upgrade to libcxx(abi), llvm, clang-tidy 16 #47771
• Fix build with libcxx16 and C++23 azure-sdk-for-cpp#8
• Fixes to make llvm 16 compile from clickhouse llvm-project#13
• Fix build with libcxx16 rocksdb#18
• Fix build with libcxx16 and C++23 aws-crt-cpp#1

TODO:

• fix vectorscan (need to make an upstream fix as we don't have it forked (and we can't have a fork due to historical reasons)) Fix compilation with libcxx 16 VectorCamp/vectorscan#144
• include [libcxx] Fix crash in std::stringstream with payload >= INT_MAX llvm-project#9 + Fix incorrect __pbump() usage (do not use it for size_t type) llvm-project#16
• use new LLVM pass manager from CHJIT.cpp
• ideally, also remove https://github.com/ClickHouse/ClickHouse/blob/master/cmake/ld.lld.in (only when we compile with Clang >=16)
• Re-enable std::assume_aligned llvm-project#14
• Remove support for std::unary/binary_function from libcxx (removed from C++17) llvm-project#15
• revert temporary fix for Woboq broken Woboq broken after Clang 16 upgrade #50077

#47709 is related (compiler upgrade Clang 15 --> 16)

Changelog category (leave one):

• Build/Testing/Packaging Improvement

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Bumped internal LLVM and libcxx/libcxxabi to 16.x