Harbour.

Harbour is a modern programming language that originated as a compiler of the Clipper programming language.

It is cross-platform and can run on DOS (MS-DOS, DR-DOS), Microsoft Windows, OS/2, GNU/Linux, several Unix variants, several BSD descendants, Mac OS X, MINIX 3, Windows CE, Pocket PC, Symbian, iPhone OS, QNX, VxWorks, OS/2 BeOS/Haiku and AIX, using the same source code and database files.

It is a powerful general-purpose language, although it is mainly used to create database and business programs. Its open source licence is similar to the GNU General Public License with the exception of support for proprietary applications, so such projects can be created and distributed with Harbour.