Support MSRV 1.63

pointer::cast_mut was stablised in 1.65, so it's too new.

src/lib.rs

@@ -606,7 +606,7 @@ impl<'addr, 'bufs, 'control> MsgHdr<'addr, 'bufs, 'control> {
     /// Corresponds to setting `msg_iov` and `msg_iovlen` on Unix and `lpBuffers`
     /// and `dwBufferCount` on Windows.
     pub fn with_buffers(mut self, bufs: &'bufs [IoSlice<'_>]) -> Self {
-        let ptr = bufs.as_ptr().cast_mut().cast();
+        let ptr = bufs.as_ptr() as *mut _;
         sys::set_msghdr_iov(&mut self.inner, ptr, bufs.len());
         self
     }
@@ -616,7 +616,7 @@ impl<'addr, 'bufs, 'control> MsgHdr<'addr, 'bufs, 'control> {
     /// Corresponds to setting `msg_control` and `msg_controllen` on Unix and
     /// `Control` on Windows.
     pub fn with_control(mut self, buf: &'control [u8]) -> Self {
-        let ptr = buf.as_ptr().cast_mut().cast();
+        let ptr = buf.as_ptr() as *mut _;
         sys::set_msghdr_control(&mut self.inner, ptr, buf.len());
         self
     }

src/sys/unix.rs

@@ -648,11 +648,12 @@ pub(crate) use libc::msghdr;
 
 #[cfg(not(target_os = "redox"))]
 pub(crate) fn set_msghdr_name(msg: &mut msghdr, name: &SockAddr) {
-    msg.msg_name = name.as_ptr().cast_mut().cast();
+    msg.msg_name = name.as_ptr() as *mut _;
     msg.msg_namelen = name.len();
 }
 
 #[cfg(not(target_os = "redox"))]
+#[allow(clippy::unnecessary_cast)] // IovLen type can be `usize`.
 pub(crate) fn set_msghdr_iov(msg: &mut msghdr, ptr: *mut libc::iovec, len: usize) {
     msg.msg_iov = ptr;
     msg.msg_iovlen = min(len, IovLen::MAX as usize) as IovLen;

src/sys/windows.rs

@@ -191,7 +191,7 @@ impl<'a> MaybeUninitSlice<'a> {
 pub(crate) use windows_sys::Win32::Networking::WinSock::WSAMSG as msghdr;
 
 pub(crate) fn set_msghdr_name(msg: &mut msghdr, name: &SockAddr) {
-    msg.name = name.as_ptr().cast_mut().cast();
+    msg.name = name.as_ptr() as *mut _;
     msg.namelen = name.len();
 }