[dvipdfmx] unknown options not reported when reading stdin

[Karl Berry]

    Processing of command line options are delayed until options
    supplied by config specials in the first page of the input DVI are
    processed.

Wow. Is that really needed/desirable? I can't think of any other program
that operates that way. Maybe it could/should be kept in dvipdfm
compatibility mode only.

Anyway, thanks for whatever you choose to do. --best, karl.