[libcxx-commits] [libcxxabi] [libc++abi] Introduce LIBCXXABI_ENABLE_DEMANGLER (PR #132130)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne requested changes to this pull request.

CC @llvm/libcxx-vendors and in particular @DanAlbert in case any changes to downstream builds are needed.

@michael-kenzel Thinking about this again, can you please add this to the libc++ release notes under `Build System Changes`? And can you also make it an error to define `LIBCXXABI_NON_DEMANGLING_TERMINATE` with a `TODO` to remove it in LLVM 22? That way, anyone building with `LIBCXXABI_NON_DEMANGLING_TERMINATE` will be notified to migrate to the new spelling when the change lands. Otherwise it's a silent behavior change.

https://github.com/llvm/llvm-project/pull/132130