[kaffe] locale bug shows it's ugly face again

[Noa Resare]

I have now reintroduced the setlocale() call to
gnu_java_awt_peer_gtk_GtkMainThread.c that seems to have vanished in an
upstream merge a while ago.

In the long run I suppose that we will use dtoa from classpath instead
of snprintf and then we will not be dependent upon LC_NUMERIC locale
setting. For now, however the patch I just committed does the job.

/noa