[committed] scripts/jar.in portability fix

[Gerald Pfeifer]

On Sat, 3 Jun 2006, Paolo Bonzini wrote:
> 2006-06-03  Paolo Bonzini  <bonzini@gnu.org>
> 
>         * scripts/jar.in: Ensure return with argument has non-empty
> argument.

I'm happy to confirm this also fixes a bootstrap failure I've been
seeing on i386-unknown-freebsd5.4.

Since the removal of fastjar from the tree, this is now the first
time libjava builds there!

Thanks!

Gerald