[Nmh-workers] mhbuild Duplicates charset of US-ASCII.

[Ralph Corderoy]

Hi,

In producing Norm's test HTML I found this ancient mhbuild duplicates
charset when it's us-ascii.

    $ for f in foo iso-8869-1 utf-8 us-ascii; do
    >     printf '\n#text/plain; charset="%s" /dev/null\n' $f |
    >     mhbuild -;
    > done
    MIME-Version: 1.0
    Content-Type: text/plain; charset="foo"
    Content-ID: <address@hidden>

    MIME-Version: 1.0
    Content-Type: text/plain; charset="iso-8869-1"
    Content-ID: <address@hidden>

    MIME-Version: 1.0
    Content-Type: text/plain; charset="utf-8"
    Content-ID: <address@hidden>

    MIME-Version: 1.0
    Content-Type: text/plain; charset="us-ascii"; charset="us-ascii"
    Content-ID: <address@hidden>

    $

Cheers, Ralph.