Make fd_tell host independent

src/sys/windows/hostcalls_impl/fs.rs

@@ -46,10 +46,6 @@ pub(crate) fn fd_pwrite(file: &File, buf: &[u8], offset: host::__wasi_filesize_t
         .map_err(|err| err.raw_os_error().map_or(host::__WASI_EIO, errno_from_host))
 }
 
-pub(crate) fn fd_tell(file: &File) -> Result<u64> {
-    unimplemented!("fd_tell")
-}
-
 pub(crate) fn fd_fdstat_get(fd: &File) -> Result<host::__wasi_fdflags_t> {
     use winx::file::AccessRight;
     match winx::file::get_file_access_rights(fd.as_raw_handle())