See: http://clisp.cvs.sourceforge.net/viewvc/clisp/clisp/doc/Why-CLISP-is-under-GPL http://clisp.cvs.sourceforge.net/viewvc/clisp/clisp/doc/Why-... NeXT wanted

See: http://clisp.cvs.sourceforge.net/viewvc/clisp/clisp/doc/Why-CLISP-is-under-GPL http://clisp.cvs.sourceforge.net/viewvc/clisp/clisp/doc/Why-... NeXT wanted to keep the Objective-C frontend to GCC proprietary, but Richard Stallman believed that would violate the GPL. I know, it's terrible: NeXT had to contribute back to a community they only wanted to take from.