bug#13580: 24.2.92; regression in calc-convert-units

[Jay Belanger]

"Roland Winkler" <winkler@gnu.org> writes:
...
>> Okay.  The user can do it that way, or ignore the "Old unit:" part and
>> get the classic behavior.  Whatever the user wants.
>
> I suggest to give Calc a user option that completely disables the
> question about an "old unit".

Okay; if the variable `calc-allow-units-as-numbers' is nil, then that
is disabled.