[C++-sig] Segfaults in object deallocation

[Jeffrey Van Voorst]

This could be misinformation, but some of the boost libraries have 
compile time flags that depend on whether or not threading is enabled.  
As an example, I was running into issues with an invalid free() with 
respect to shared_ptr (in the cctbx project). Unfortunately, (for your 
case) the fix was to download a more recent version of the cctbx project 
that no longer exhibited this problem.

In short, the boost smart pointers, boost spirit, etc. implementations 
vary depending on the compile time options.  I don't know if 
boost.python has options.

Also, I found that with these issues it is generally easier to pinpoint 
the problem when the code is compile without optimization.

--Jeff