[Feature] cfunction_name for CStr

[flaviojs]

Hi, I am converting C code to rust, currently at a piece of code with __func__.

I would like to replace it with a nul-terminated CStr, so I propose the creation of cfunction_name!().

The macro would produce the C-string literal c"funcname", which is available starting with Rust 1.77 https://doc.rust-lang.org/nightly/edition-guide/rust-2021/c-string-literals.html