bug#27952: 26.0.50; Combine archive-int-to-mode and tar-grind-file-mode

[Stefan Monnier]

> +(defalias 'archive-int-to-mode 'file-modes-number-to-symbolic)

Make it a `define-obsolete-function-alias`.

>  (defun tar-grind-file-mode (mode)
>    "Construct a `rw-r--r--' string indicating MODE.
[...]
> +MODE should be an integer which is a file mode value.
> +For instance, if mode is #o700, then it produces `rwx------'."
> +  (substring (file-modes-number-to-symbolic mode) 1))

LGTM.  A second step might be to mark this function as obsolete and
update all the call sites so they are happy with the output format of
`file-modes-number-to-symbolic`.


        Stefan