Hi Donald...

I'm sorry I missed this discussion the first time, I noticed this while
glancing through ChangeLog...

This change disturbs me a little, and I think it has the potential to
break a lot of things for a lot of people.  It seems like the best way
to handle this is to support both, and let a particular configuration
specify the default, much like a target configuration can specify
DEFAULT_PCC_STRUCT_RETURN or DEFAULT_VTABLE_THUNKS.  This would allow
the configurations for IRIX, Ultrix, Linux, NetBSD, etc. to keep
compatibility with all of their existing installed base, as well as
allow your customer's target (who's bug it fixes, according to your
original message) to work properly, or even allow the user to choose
at compile time (e.g. -fnew-stdarg-abi, or something).

Breaking a C++ ABI is one thing (because, for one, it's so easy to do),
but stdarg/varargs is a pretty fundamental part of the C ABI... it seems
like one would want to avoid such an incompatibility at all cost.

-- 
        -- Jason R. Thorpe <thorpej@zembu.com>