[rfc] alpha-linux changing to 128-bit long double

[Richard Henderson <rth at twiddle dot net>]

So I'm thinking that I'd like to finally get around to changing to
128-bit long double for alpha-linux.  I'm undecided how to go about
doing this though.

The math routines would be easy to version, but things like printf
definitely aren't.  Because of that, I was thinking that perhaps
it might be best to just increment the soname to libc.so.6.2.  Which
would be a good opportunity to get rid of some awful compatibility
code in the alpha-linux glibc bits.

I would be comfortable getting all this done for glibc 2.3.4, and
just say "use an older release if you don't want this abi change."
Seems to me the ifdeffery (and worse, makefile ifdeffery) would be
too awful to considering supporting both modes simultaneously.

As for gcc, I suppose I'll have to do something like a different
configuration name, such as alpha-dec-linux-glibc6.2?  The patches
to gcc (for any recent version) should be small; the support is
already present because of Tru64, just have to turn it on.

Cc'ed to debian-glibc, since they're the only currently viable alpha
distribution that I'm aware of.  I see yall are still using glibc
2.3.2.  What are debian's plans here wrt the next release (if there's
ever to be one)?

Myself, I have been thinking about working on a Fedora Core port for
Alpha, and it would be easiest if I just started out with the new
long double size.


r~