pub fn set_out_dir(args: &mut Vec<String>, dir: &Path)Expand description
Redirect rustc’s output directory. Same fold-and-add semantics
as set_crate_type: strip every existing form, append one
fresh pair. Handles --out-dir <DIR>, --out-dir=<DIR>, and
the -o <PATH> short form (rare in cargo invocations but
possible — we drop it because --out-dir wins for --crate-type cdylib).