cp: Use FICLONE ioctl constant from linux-raw-sys

The current ioctl operation code for FICLONE is fully open-coded instead
of using the ioctl macros, which makes it non-portable to other
architectures including mips, arm & powerpc. Get the constant from the
linux-raw-sys crate instead, which is already a transitive dependency.

Cargo.toml

@@ -303,6 +303,7 @@ iana-time-zone = "0.1.57"
 indicatif = "0.17.8"
 itertools = "0.14.0"
 libc = "0.2.153"
+linux-raw-sys = "0.9"
 lscolors = { version = "0.20.0", default-features = false, features = [
   "gnu_legacy",
 ] }