func Uname(uname *Utsname) error {
	mib := []_C_int{CTL_KERN, KERN_OSTYPE}
	n := unsafe.Sizeof(uname.Sysname)
	// Suppress ENOMEM errors to be compatible with the C library __xuname() implementation.
	if err := sysctl(mib, &uname.Sysname[0], &n, nil, 0); err != nil && !errors.Is(err, ENOMEM) {
		return err
	}

	mib = []_C_int{CTL_KERN, KERN_HOSTNAME}
	n = unsafe.Sizeof(uname.Nodename)

const (
	paxNone     = "" // Indicates that no PAX key is suitable
	paxPath     = "path"
	paxLinkpath = "linkpath"
	paxSize     = "size"
	paxUid      = "uid"
	paxGid      = "gid"
	paxUname    = "uname"
	paxGname    = "gname"
	paxMtime    = "mtime"
	paxAtime    = "atime"
	paxCtime    = "ctime"   // Removed from later revision of PAX spec, but was valid
	paxCharset  = "charset" // Currently unused

		if v == "" {
			continue // Keep the original USTAR value
		}
		var id64 int64
		switch k {
		case paxPath:
			hdr.Name = v
		case paxLinkpath:
			hdr.Linkname = v
		case paxUname:
			hdr.Uname = v
		case paxGname:
			hdr.Gname = v
		case paxUid:
			id64, err = strconv.ParseInt(v, 10, 64)
			hdr.Uid = int(id64) // Integer overflow possible
		case paxGid: