DR handling for C++

[Mark Mitchell <mark@codesourcery.com>]

I've been asked to provide my input on the handling of DRs in the C++ 
front end.

Unfortunately, I don't have the messages from the original thread, so 
I'm off starting a new thread.

I certainly agree with Matt and Nathan that there's no point in 
supporting C++98 separately from C++03.  I also agree that new features 
in future revisions of C++ should be supported only under a flag.  I 
think that fixes for existing features, however, should be incorporated 
into the C++03 mode, even if they don't show up in C++03 itself.  (A 
"defect repot", after all, is supposed to refer to a bug in the 
standard.)  I think the threshold for incorporating such fixes should be 
that the fixes are in WP status, in general, although I'd consider other 
fixes if it seems clear that the commitee is going to accept the change 
and the change seems important.

In the particular case of PR 15049, I think we should go with Matt's 
approach.  I'm not sure that, in general, I'd want to leave in support 
for what the commitee basically considers to be bugs in C++03, but in 
this case it looks very easy to do that, so we should probably go ahead.

I think that part of the confusion here comes from the 
-pedwarn/-fpermissive situation.  I think -fpermissive should just be 
removed.  I think that many of our pedwarns should become errors, many 
should become warnings, -pedantic-errors should be off by default.

-- 
Mark Mitchell
CodeSourcery, LLC
(916) 791-8304
mark@codesourcery.com