Harbour RC2 is very reliable version so you can download and test with
any clipper source from http://sourceforge.net/project/showfiles.php?group_id=681

whatsnew here:
http://harbour-project.svn.sourceforge.net/viewvc/harbour-project/tag...

you can subscribe maling list for assistance from here:
http://lists.harbour-project.org/mailman/listinfo/harbour-users

Harbour have this supported platforms:
- Win32
- Win64
- OS/2
- Linux
- Darwin PPC
- Darwin Unibin
- HPUX
- BSD