I followed the instructions
here for building c::b, which worked fine, although I skipped making the app Bundle since I will just be running c::b from the Terminal. Okay, on to the plugin issues.
The first problem is that the plugins were compiled and installed to /usr/local/lib/codeblocks/plugins (I used /usr/local as the default prefix) whereas c::b expects them to be in /usr/local/share/codeblocks. As a quick fix, I simply copied the files to that location. Now c::b does find them and (tries to) load and activate them.
The next problem is that several of the default plugins cause c::b to crash during plugin activation. The only ones that worked for me were: astyle, autosave, projectsimporter, and scriptedwizard. Classwizard is unique in that it will work by itself but not if the other 4 that work are loaded, so I assume there is some kind of conflict going on there.
Some of the contrib plugins don't compile, but wxsmith did. However, it's one of those that crashes c::b.
If anyone is working with c::b SVN on OS X, I could use some pointers.