[kaffe] with-rt-jar option for configure

[Kiyo Inaba]

Hi,

The option for configure '--with-rt-jar' needs argument to specify the
rt.jar file used instead of compiling it by using freshly made kaffe.
Isn't it better to force using './rt.jar' rather than current '.'
I'd like to keep several different versions of rt.jar file in one
directory with having different name but with current version, I
have to put each into different directory.

Kiyo