Silly C++ formatting of error messages.

[Per Bothner]

> $ gcc module1/ident.c module2/ident.c
> ident.c:3:Parse error before 'char'

We might consider a style like we do for function names:

        In directory module1:
        ident.c:3: Parse error before 'char'

The problem is that tools like emacs don't understand this.
That can be fixed for emacs, though.

We could use a flag to control this style.  For now I would
make the default off.  If people like it, and emacs is fixed,
we could make the default on.
-- 
	--Per Bothner
per@bothner.com   http://www.bothner.com/~per/