[2.90.9] planning for the next release

[Martin v. Loewis]

> It might be better to come up with a patch before it gets sent to the
> gcc-list for discussion. It sounded like Martin was on the right track, 
> but that Jason wants the option of building both libraries?

I thought that Jason merely wanted an to *build* both libraries,
primarily to see whether the compiler still accepts all code in it (I
guess). That should be possible, at least trivially by

EXTRA_TARGET_LIBS="libstdc++ libio" configure  --other-options

and having $EXTRA_TARGET_LIBS at the end of target_libs.

When it comes to installation, you'll have to pick one or the other,
because the compiler has to chose specific include files and libraries
(unless we want -flibstdc++=v3, but I certainly don't ...) So I'd
expect 'build all libraries' to be an expert's option only, at least
until we know how they can be installed concurrently.

Regards,
Martin