[3.14] gh-100218: correctly set `errno` when `socket.if_{nametoindex,indextoname...

[3.14] gh-100218: correctly set `errno` when `socket.if_{nametoindex,indextoname}` raise `OSError` (GH-140905) (#141284)

gh-100218: correctly set `errno` when `socket.if_{nametoindex,indextoname}` raise `OSError` (GH-140905)

Previously, socket.if_nametoindex() and socket.if_indextoname() could raise
an `OSError` with a `None` errno. Now, the errno from libc is propagated.
(cherry picked from commit 3ce2d57b2f02030353af314d89c5f6215d2f5c96)

Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>