Hello,

I prepared the same, but did not push it yet. Actually, I wanted to package 
the vorbis-tools, and got sucked into a dependency chain that started with 
curl and currently ends with ghostscript...

> +    (inputs `(("xz" ,xz)))

You do not need this; it is only used for unpacking, which is handled 
automatically.

Concerning the license, I have
   (license (bsd-style "file://COPYING"
                       "See COPYING in the distribution."))
instead of
+    (license bsd-3)))

My reason was that the license contained a line
"Neither the name of the Xiph.org Foundation nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission."
So this is not precisely the original BSD-3 license, which does not mention 
Xiph.

What is our policy here?

So I would suggest the following more comprehensive patch.

Andreas