[trasz]

On the other hand, choosing to use GPL would prevent it from being integrated anywhere else. You'd also lose the patent protection granted by CDDL.

[vetinari]

It's not like they couldn't use dual licenses, like Mozilla did at the time, for example.

[aidenn0]

Any license more liberal than the GPL would also be fine. For example: MIT/X11, 2-clause BSD, or Ruby's license.