Patch for sC++ to GNU C++.

[Joe Buck]

>     Joe> As I mentioned, the alternative is to do something like
>     Joe> c-parse.in (the technique used to share the C and Objective-C
>     Joe> parsers).
> 
> You're probably noticing that I'm being contrary.  :-) Here's my
> problem:
> 
>   o If we add a new front-end and duplicate all the files, we've
>     duplicated all the files.  This necessitates changes in two
>     places.  We have *way* too much of this as it is.

Please cd to gcc/objc and look around.  Do you see duplication?  No, you
only see six source files.  The only duplication is in objc-parse.y: it
and c-parse.y are both obtained from c-parse.in.

Just the same, I have to agree with you when you say:

> That leads me to conclude that the right thing to do at the moment is
> to have the people interested in the extension maintain their patches,
> separately from g++.

I think so too, for now (though it appears that Jan's extensions are far
less disruptive than signatures).  But I think that the patches could be
restructured to make them easier to integrate later on: something like an
sc directory plus a smaller patch to the C++ part.  I think that the way
Objective-C is done is a good model.  This might turn Jan's patch into a
much smaller patch plus an add-on directory.