[Vala] error messages from valac have some kind of extra formatting that confuses emacs compilation mode

[Dan Hitt <dan hitt gmail com>]

When i compile something with valac, like
     valac --pkg gio-2.0 some_program.vala
the error messages apparently include some extra formatting characters.

So, instead of getting only
   some_program:48.33-48.33: blah blah blah blah,
in addition some leading characters like "ESCAPE [001m" are emitted.

These presumably make the output red or bold face or something.

But they confuse the compilation mode in emacs, so that it doesn't
know where to jump to
in order to walk through the errors in the source tree.

I looked at the man page for valac, and did not see any way to turn
off the extra formatting.

I presume there must be, because after all these years i can hardly be
first to have this problem.

Thanks in advance for any clues, even RTFM if you point me to the
right fine manual to read!

dan