pub const BUNDLED_DIR: &str = "<cinrs>";Expand description
The directory the bundled headers appear to live in.
It is not a directory at all — the headers are strings inside this crate —
but a diagnostic has to name the file it is talking about, and
<cinrs>/stdio.h says both which header it is and that it is ours. The
angle brackets keep it from being mistaken for a path that exists.