Guile 2 compatible release tarballs

[Geert Janssens]

Let me bring guile 2 up again. The current status is this:
- gnucash is ready for guile2, but depends on a very recent version of swig to generate guile 2 
compatible wrapper code
- in fact *very* recent: swig 2.0.10 has been release today and is the first version of swig 
capable of generating guile 2 compatible wrapper code

Does that mean we *require* swig 2.0.10 ? No. GnuCash 2.5.x works perfectly fine with guile 
1.8 and older versions of swig generate code that works fine with guile 1.8.

So if you start from our svn/git repository, it's just a matter of personal choice: do I want guile 
2 ? Ok, I'll have to make sure I get swig 2.0.10. If that's not an option yet, stick with guile 1.8 
and an older version of swig. Working code will be generated in both cases.

But what about our tarballs ? There we currently have a problem. The tarballs are shipped 
with pre-generated wrapper code. So a consumer of our tarballs doesn't have the choice: it 
has to find a guile version compatible with the pre-generated wrapper code. The currently 
pre-generated wrapper code is not guile 2 compatible, because it's still generated with an 
older swig version.

This mostly affects distro packagers. Most distros are currently switching to guile 2. Since our 
tarballs are not guile 2 ready, distros still have to provide guile 1.8 as well.

Also it sends the wrong message: we claim gnucash is guile 2 ready, but we ship a tarball 
that doesn't work with guile 2 ? Not good.

So here's my request: can we do future 2.5.x releases on a machine that has swig 2.0.10 
installed ? I know it's incredibly recent software, but it would correct the message we send 
and make the lives of several distro packagers more easy.

With "future", I don't mean 2.5.2 that's currently in the middle of a release, but perhaps 2.5.3 
end of June would be possible ?

There is one more devil in the details: while the tarballs for 2.5.x should ideally be generated 
on a system with swig 2.0.10, tarballs for any possible future 2.4.x releases should *not*. 
Reason: swig 2.0.10 drops support for guile 1.6, while we claim gnucash 2.4.x does support 
guile 1.6.

So either 2.4.x and 2.5.x releases should be done from different machines or we drop support 
for guile 1.6 as well in the next 2.4.x release (if any).

What do you think ?

@John: since you are currently doing most releases, the question is probably aimed mostly at 
you: are you willing to install swig 2.0.10 on a machine you will be generating tarballs on ?

Geert