[R-SIG-Mac] Debugging package code in Xcode?

[Duncan Murdoch]

I'd like to use Xcode to debug the rgl package, which is crashing 
sometimes in X11 on OSX.   In the past, I've done this for debugging R 
itself, and have a project set up for that.  I can attach to the process 
ID, and then I see rgl.so is loaded, but I can't see how to set a 
breakpoint in the rgl.so code.

Has anyone else done this before?  Can you point me to step-by-step 
instructions?


Duncan Murdoch