Created attachment 195613 [details] [review]
Allow automagic selection of guile

We keep --with-guile, but default to automagic selection. This makes
life easier for distributors, who can then rely on this if they know
they simply want to build against the guile version that is available by
default.

Note that while aisleriot compiles with guile 2.0, it still has a nasty crasher in freecell (bug 649730), so you really shouldn't ship that in a distro.

(In reply to comment #0)
> I know automagic selection of guile was once in git, but got removed and
> replaced by --with-guile. I think we should allow --with-guile, but default to
> automagic selection.
> 
> This makes life much easier for packagers, as they won't have to tweak the
> aisleriot packaging when the distro moves from guile 1.8 to 2.0, and then to
> 2.2: it will just work.

Won't they have to update the build dep info anyway?

In general, I'm opposed to automatic dependency & feature selection, since it produces indeterministic results. 

Note that guile 2.0 will become the default once bug 649730 is fixed.

(In reply to comment #2)
> Note that while aisleriot compiles with guile 2.0, it still has a nasty crasher
> in freecell (bug 649730), so you really shouldn't ship that in a distro.

We don't ship guile 1.8 in openSUSE anymore, so there's no other option...

(In reply to comment #3)
> > This makes life much easier for packagers, as they won't have to tweak the
> > aisleriot packaging when the distro moves from guile 1.8 to 2.0, and then to
> > 2.2: it will just work.
> 
> Won't they have to update the build dep info anyway?

It depends how you choose to do the packaging. For openSUSE, since we know we only have one version of guile, we build against "guile-devel". So we don't have to update the build dep when the guile version changes.

> In general, I'm opposed to automatic dependency & feature selection, since it
> produces indeterministic results. 

In this case, it's not an optional dependency or feature, so I wouldn't say it's producing indeterministic results. It's just using the latest supported version of guile available by default, instead of 1.8 (or 2.0 in a few days).

I committed a different patch to master. It adds --auto, but implements it differently, and does not change the default, so you have to explicitly specify --with-guile=auto to get automagic.