SourceForge URLs changed

[ludo@gnu.org (Ludovic Courtès)]

Hello,

Apparently SourceForge did a massive URL change, *and*, for extra fun,
failing mirrors return 200 instead of 404.

At first sight we need at least the mirror URL update in commit
cd4c41fdcf469524161fbbec58c2756f36bcef56.

But that’s not enough.  It seems that URLs now have the form:

  /PACKAGE/PACKAGE/VERSION/PACKAGE-VERSION.tar.gz

so for we have things like:

  http://ufpr.dl.sourceforge.net/project/detox/detox/1.2.0/detox-1.2.0.tar.bz2
  http://ufpr.dl.sourceforge.net/project/netcat/netcat/0.7.1/netcat-0.7.1.tar.bz2

Apparently some of the URLs we use are fine, such as smartmontools.

Others seem to be gone, such as clusterssh.

As a first step, commit bfcb3d767bbc24dc6c6d834619073351fbcc61b5
improves ‘guix lint’ to report suspiciously small responses:

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix lint clusterssh
gnu/packages/admin.scm:702:2: clusterssh-3.28: URI http://sourceforge.net/projects/clusterssh/ returned suspiciously small file (174 bytes)
gnu/packages/admin.scm:705:12: clusterssh-3.28: all the source URIs are unreachable:
gnu/packages/admin.scm:702:2: clusterssh-3.28: URI http://ufpr.dl.sourceforge.net/project/clusterssh/clusterssh-3.28.tar.gz returned suspiciously small file (639 bytes)
gnu/packages/admin.scm:702:2: clusterssh-3.28: URI http://heanet.dl.sourceforge.net/project/clusterssh/clusterssh-3.28.tar.gz returned suspiciously small file (639 bytes)
gnu/packages/admin.scm:702:2: clusterssh-3.28: URI http://freefr.dl.sourceforge.net/project/clusterssh/clusterssh-3.28.tar.gz returned suspiciously small file (639 bytes)
…
--8<---------------cut here---------------end--------------->8---

Then we could fix individually things like netcat, detox, and others,
but it’s not clear to me whether it’s a systematic change or not.

Would anyone like to investigate?  :-)

Thanks,
Ludo’.