Qemu does not shutdown with vnc enabled on OS X

I am running OS X 10.8.2 and Qemu 1.3.50 from your git repository.

Running

    qemu-system-i386 <image>

works fine. I can quit the process using ctrl-c.

When I try to use

     qemu-system-i386 -vnc :<port> <image>

ctrl-c does nothing and I have to kill the process trough the activity monitor.
Furthermore terminating the process from my java program does not work either. 
I have also posted a question on Stackoverflow: http://stackoverflow.com/questions/13798367/qemu-does-not-shutdown-with-vnc-enabled-on-os-x

Thanks
Leander