autogen install or upgrade fails

[Bruce Korb]

On Thu, May 4, 2017 at 7:07 AM, Ryan Schmidt <ryandesign at macports.org> wrote:
> Looks like homebrew has patched it:
>
> https://github.com/Homebrew/formula-patches/blob/master/autogen/allow-guile-2.2.diff
>
> I didn't see any upstream bug report or code change related to this so the issue probably needs to be reported to the developers of autogen.

-#else
-# error unknown GUILE_VERSION
- choke me.
#endif

15+ years ago, Guile had a habit of changing their interfaces without
a lot of notice causing dependent projects to fail without notice.
The failures were obscure to me and downright obtuse to my "clients".
Consequently, I had to develop all that convolution to ensure that
nobody tried to build AutoGen against a version of Guile that I had
not personally verified. I haven't stumbled into problems
like the Guile 1.4 -> Guile 1.6 transition or the Guile 1.6 -> Guile 1.8
transition in a number of years now. Therefore, I think it is time to
change the hard error into a warning so that if there is an obscure
failure and the warning is present, then my clients can test against
an older Guile just to see if that is the issue. There were so many
problems 15 years ago and the Guile team was so intransigent about
they being correct to change interfaces that, to this day, I do not
trust them to not change the interface. :(