Re: base64 behavior is not MIME compliant

[Richard M. Stallman]

    I received a piece of email which passed through an older MTA.  This
    MTA inserted a ! and a newline after every 1000 characters of a very
    long line of base64-encoded data, which used to be common behavior.
    When Gnus tried to display this email, it failed, because the !
    characters were not recognized as valid base64 encoding.

Maybe I misunderstood what you were asking for.  I thought you
were asking us to make additional base64-decode-region signal
errors in cases where currently it does not.  But now it looks
like you are asking for it to accept input that now gives
an error.

Could you give a self-contained description of the change that you are
requesting in the behavior of this function?