Updating of0.84 project to of0.9: troubles with ofEvent

Hi,
I'm in the process of moving a rather large Win of0.84 project to of0.9 on OSX. I removed all Windows specific code, but now I ran into another problem during compilation:

ofBaseEvent<of::priv::Function<T,Mutex>,Mutex>::remove(make_function(listener,method,priority));
ofEvent.h:284:58: No matching member function for call to 'make_function'

ofBaseEvent<of::priv::Function<T,Mutex>,Mutex>::add(make_function(listener,method,priority));
ofEvent.h:279:55: No matching member function for call to 'make_function'

Any hints?
OSX 10.10, XCode 7 with OSX 10.10 SDK (copied over from XCode6)