Decklin Foster sent me an email this morning:
The GPL says that you can’t add any additional restrictions when distributing a derived work. So, while “attribution + share alike” would be compatible, anything involving “no derivs” or “non-commercial” would be incompatible with the GPL. Even if the CC license allowed you to add more restrictive terms (I haven’t read it), you would still end up with something not legally distributable, because the GPL’ed parts would no longer give you permission to distribute them under the GPL.
The BSD/MIT license explicitly grants you the right to sublicence without stating any restrictions, so there is no problem here. (nb: while the BSD license is “attribution”, old-style 3-clause BSD license is “attribution + put my name on all your advertising materials”, which makes software licensed under such terms GPL-incompatible.) BSD-licensed software is GPL-compatible because (a) you can add any terms you want to the BSD’ed parts, and (b) the restrictions of the BSD license are a subset of those stated in the GPL.