On Wed, Feb 21, 2024 at 11:55 PM Stephane Chazelas
<stephane@chazelas.org> wrote:
>
> $ ((1+|ÃÃÃÃÃÃ))
> zsh: bad math expression: operand expected at `|ÃÃÃÃ\M-C...'

As Stephane also pointed out, ÃÃÃÃÃÃ is a valid identifier, so it's
not farfetched that someone could make a typo using one in a math
expression.

The code added here could be made into a utility [metalen() is almost
there] but as I don't know of anywhere else this is needed, I just
inlined it.  I looked through the other mb_* routines in utils.c but
they all appeared to do what would be extraneous work for this
purpose.