Patch for Preview: jcf-io.c and Win32 case-insensitive filename handling

[Andrew Haley]

Tom Tromey writes:
 > 
 > It is hard to imagine that this will be useful outside the gcj front
 > end.  Let's put it there unless somebody objects.

Please fix the layout issues and rename the new file to win32-host.c.

Then I'll approve it.

Thanks,
Andrew.