> If you use BSD, MIT, etc, you can't combine any GPL licensed code. In the LedgerSMB project, I have started licensing core framework libraries under the BSD

> If you use BSD, MIT, etc, you can't combine any GPL licensed code. In the LedgerSMB project, I have started licensing core framework libraries under the BSD license because that should allow easier bridging to proprietary software. We started doing this with PHP libraries, but then decided that Perl shouldn't be a second-class language integration-wise. There's no reason that GPL code can't depend on BSD code. These licenses can co-exist and one can choose to license some parts of a project under the GPL and others under a BSD license.