MacOSX

When compiling on MacOS X I get the message: Undefined symbols: ___dso_handle.
You have an old version of XCode, you need at least version 2.4.1 or "gcc version 4.0.1 (Apple Computer, Inc. build 5367)"
When I run the A01 Example and type "exit" at the prompt a message appears that I need to close the interactive window. However, the window does not have an active close button and therefore does not close.
Typing ctrl-c at the prompt will close the window. We suspect the close button does not work because of some threading problem with Java and Native threads on MacOS X.