Why did devel/bison grow a dependency on xz?

[eric%cirr.com@localhost (Eric Schnoebelen)]

I'm curious why devel/bison grew a dependency on archivers/xz?

The dependency is an implicit one, based on setting EXTRACT_SUFX
to .tar.xz.  

I guess the question is, why was it essential to create the
dependency when bison is still also being made available as a
"traditional" .tar.gz?

I encountered this while trying to bring a(n admittedly antique)
SS20 running NetBSD 2.1 up to date using pkgsrc-2012Q3.  The
poor little beast spent a couple of days trying to build
gcc-3.4, so it could build xz, which then failed to build. And
building xz was effectively pointless, as the bison sources were
available as .tar.gz.

Objections to reverting devel/bison to using the more
"traditional" .tar.gz tarball?

--
Eric Schnoebelen                eric%cirr.com@localhost         
http://www.cirr.com
            Okay, who put a "stop payment" on my reality check?