Hi Guix,

attached are a couple of patches to the icedtea6 package that make it a
little easier to reuse build phases for a future icedtea7 package.  They
also fix a problem in the original package where a standard build phase
is overridden.

I must admit to being rather clueless when it comes to coming up with
appropriate commit messages for these changes, so I'd appreciate
suggestions to improve them.

~~ Ricardo