Rollup merge of #70201 - cuviper:clone_into, r=dtolnay

Small tweaks in ToOwned::clone_into

- `<[T]>::clone_into` is slightly more optimized.
- `CStr::clone_into` is new, letting it reuse its allocation.
- `OsStr::clone_into` now forwards to the underlying slice/`Vec`.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/libstd/sys/windows/os_str.rs b/src/libstd/sys/windows/os_str.rs
index 6aab028873e..2f5fc72ab44 100644
--- a/src/libstd/sys/windows/os_str.rs
+++ b/src/libstd/sys/windows/os_str.rs
@@ -159,6 +159,10 @@ impl Slice {
         Buf { inner: buf }
     }
 
+    pub fn clone_into(&self, buf: &mut Buf) {
+        self.inner.clone_into(&mut buf.inner)
+    }
+
     #[inline]
     pub fn into_box(&self) -> Box<Slice> {
         unsafe { mem::transmute(self.inner.into_box()) }