[llvm] [llvm] Make charset constexpr (NFC) (PR #137535)

[Nikita Popov via llvm-commits]

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

LLVM generally does not use const for local variables, let alone constexpr.

If there were some specific reason to do this (e.g. to force constexpr evaluation of an initializer) that would be one thing, but just adding a constexpr to essentially a single random variable in a large code base doesn't make a lot of sense to me.

https://github.com/llvm/llvm-project/pull/137535