It appears that if AddMessage() is called with a message containing a newline, the game crashes under Mac OS X. I haven't found out why (maybe some endianness problem), but newlines don't belong in the status messages anyway, so they should be removed from the two calls in rt_game.c (the "100 Life Item Points" message and the "Dopefish Death Cam".)
Actually, the reason why it's only until now that I found out about this bug, is that I never got 100 life item points even though I played through the entire game in OS X to test it. I always destroy all 'triads' in every level in order to get the 'Bull in china shop' bonus!