[libc] [llvm] [libc][math][c23] Implement canonicalize functions (PR #85940)

[Nick Desaulniers via llvm-commits]

nickdesaulniers wrote:

> Since the issue is that the implicit conversion to bool is failing, the easiest solution is likely to add a `static_cast<bool>` to the statement.

Cant leave the buildbots red for long: https://github.com/llvm/llvm-project/pull/86736

https://github.com/llvm/llvm-project/pull/85940