[iOS] App crashes at startup since upgrading to Mavericks

[simedj]

I recently upgraded to OSX Mavericks, when I next opened XCode 5 it told me I had to install 5 updates to continue, so I let it. Now, my app which was already built in the simulator crashes on startup and when I rebuild this still happens - I get this log output:

The iOS Simulator libSystem was initialized out of order. This is most often caused by running host executables or inserting host dylibs. In the future, this will cause an abort.
Assertion failed: (bundle != NULL), function open_libgl, file /usr/local/ogre/ogre1.9/RenderSystems/GLES2/src/gles2w.cpp, line 87.

I haven't worked on this app very recently so it's not all very fresh in my mind but I'm 99% sure it was working before, I didn't leave it in a broken state.

I seem to spend an inordinate amount of time fighting OSX/XCode! Can anyone suggest what's gone wrong this time?!