thanks to everybody for the suggestions on a licence for pd-patches!
i think that i'll use the gpl, though i have not yet decided on the exact version... it allows free sharing, and to include other work without having to think too much about any licence-issues/compatibilities. and it can not be mistaken for 'public domain' too easily. and if someone wants to use anything for a non free purpose, i will have to be asked to 'dual-licence' it, much like it is the case with the cc-license. the only caveat might be the case when i have used some other gpl-work, and someone wants to make an non free app from it. (this person then has to ask a few people for permission to use the code...). but that is of course much better than not to be able to build on other gpl-code at all. (and it does not happen that often anyway...)