duplicating apache-ant-*-bin distfiles?

[Alexey Dokuchaev]

hi there,

today i've noticed that i have two suspiciously similar files in my
$DISTDIR:

$ ll apache-ant-1.9.4-bin.*
  .. bla-bla.. 	4351965 30 Apr  2014 apache-ant-1.9.4-bin.tar.bz2
  .. bla-bla..  8309406 30 Apr  2014 apache-ant-1.9.4-bin.zip

their contents look the same, just packed differently (notice how .zip
sucks ass).

why two files?  because `devel/apache-ant' wants .tar.bz2, but both
`java/openjdk6' and `java/openjdk7' want .zip.

could we do something about this, so everyone (users, buildbots) would
not have to download the same stuff [more than] twice?  thanks,

./danfe