How to set 'start-with-shell' off?

During a debug session (Debug|Simulator) I got this. How do I set 'start-with-shell' off? (I have looked and can't find any docs on how to do this).

[Session started at 2011-03-10 09:05:22 -0800.]
GNU gdb 6.3.50-20050815 (Apple version gdb-1510) (Wed S开发者_StackOverflow中文版ep 22 02:45:02 UTC 2010)
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This GDB was configured as "x86_64-apple-darwin".sharedlibrary apply-load-rules all
Attaching to process 1734.
Detected an attempt to call a symbol in system libraries that is not present on the iPhone:
pthread_mutexattr_destroy$UNIX2003 called from function pthreadMutexAlloc in image PointsEncodeDecode.
If you are encountering this problem running a simulator binary within gdb, make sure you 'set start-with-shell off' first.
Program received signal:  “SIGABRT”.
kill
quit

The Debugger has exited with status 0.(gdb) 

I got this issue since I updated to XCode 3.2.5 with iOS 4.2

My problem came from native librairies I was using, that needed to be recompiled under iOS4. It seems that this iOS version is not fully binary compatible with the previous one...

Otherwise, try the new version of XCode 4 and iOS4.3 to see if it solves your problem.