Put "Error:" before error output

[Sven Panne]

2015-01-23 12:55 GMT+01:00 Konstantine Rybnikov <k-bx at k-bx.com>:
> If warnings will be treated as errors it's fine to have "Error:" shown for
> them, I think.

+1 for this, it is how e.g. gcc behaves with -Werror, too. So unless
there is a compelling reason to do things differently (which I don't
see here), I would just follow conventional behavior instead of being
creative. :-)