Hi Guix,

this commit message is a bit hairy.  Instead of just updating gcj-4.8 to
the latest version (4.9) I also made it inherit from our default “gcc”
and renamed it to just “gcj”.  Likewise, “ecj-bootstrap-4.8” is updated
to version 4.9 and renamed to just “ecj-bootstrap”.

The “gcj-4.8” package predates our use of a default “gcc” variable.

The same patch also updates the two packages that used “gcj-4.8” as an
input.

“ecj-bootstrap-4.8” appears to be broken on mips64el and armhf (using it
to bootstrap GCJ results in a broken GCJ on these platforms), and I’m
hoping that the situation is different for the 4.9 release.

~~ Ricardo