/// This macro creates a zero-overhead &CStr by adding a NUL terminator to
/// the string literal passed into it at compile-time. Use it like:
///
/// ```
/// let some_const_cstr = const_cstr!("abc");
/// ```
///
/// The above is roughly equivalent to:
///
/// ```
/// let some_const_cstr = CStr::from_bytes_with_nul(b"abc\0").unwrap()
/// ```
///
/// Note that macro only checks the string literal for internal NULs if
/// debug-assertions are enabled in order to avoid runtime overhead in release
/// builds.