Hi Guix,

GCJ is likely broken on MIPS and ARM (as can be seen in the way Ant
fails to build on these platforms), but the package builds just fine.
That’s probably because we are not running the libjava tests, which
require dejagnu.

The attached patch adds dejagnu to the native-inputs and replaces the
check phase to build and run the libjava tests.

This patch will likely cause the GCJ package to fail on MIPS and ARM,
but that’s expected and helpful, as it should give us a hint how to make
it work on these platforms.

~~ Ricardo