The fox eclass accumulated a lot of cruft over the years. Specifically,
it includes quite a bit of code to support versions loong gone from our
tree. The only officially supported versions now are 1.6 and 1.7.
Thus, I've edited it a bit. Main points are EAPI2 phase support and a
lot of variable quoting.
Posting this for review as the diff is rather largish and I'm known to
have the usual typo in it ;)