[clang] Add option -fstdlib-hardening= (PR #78763)

[Fangrui Song via cfe-commits]

MaskRay wrote:

I am on the fence whether a driver option is really needed. It is a very shallow layer of extra abstraction that a curious reader has to look through. I guess I'll not object to this, though.

https://github.com/llvm/llvm-project/pull/78763