[klibc] rename, renameat: Use renameat2() system call

New architectures only define the renameat2() system call, which was
added in Linux 3.15.  Define rename() and renameat() as wrappers for
it if necessary.

Link: https://www.zytor.com/pipermail/klibc/2018-July/003996.html
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
4 files changed