Remove add-ons mechanism

[Joseph Myers]

On Thu, 28 Sep 2017, Zack Weinberg wrote:

> On Thu, Sep 28, 2017 at 1:49 PM, Joseph Myers <joseph@codesourcery.com> wrote:
> >
> > Add-ons involve significant, little-used complexity in the glibc build
> > system, and make it hard to understand what the space of possible
> > glibc configurations is.  This patch removes the add-ons mechanism.
> 
> I don't disagree with this patch exactly, but I was thinking of using
> the add-ons mechanism to prototype a CSPRNG addition to glibc and I'd
> like to ask how you think that should be done instead (and more
> generally, how you think new features that people might want to
> experiment with but that are not yet ready for prime time should be
> distributed -- branches are Not Great, as one has to keep rebasing
> them)

I'd expect branches to be used.  That way the feature is in a form 
actually more or less like how it might be added to glibc (including e.g. 
adding interfaces to existing headers if appropriate).  I don't think 
frequent rebasing is really needed.

If you also want the feature to be usable by people with older glibc 
versions without needing to update / rebuild glibc, that would indicate 
having a separate library version of the feature, with some form of 
automation to copy sources from one to the other.

-- 
Joseph S. Myers
joseph@codesourcery.com