When a thread under Python 2.3 produces a synchronous signal 
(like a SIGSEGV) the signal is blocked and does not get handled by 
the Python interpreter. 

Python 2.4 corrected this behavior and signals sent to a thread are 
acknowledged, and then handled  the signal default behavior unless  
overridden with a signal handler. (in which case the python signal 
handler is run on the main thread.)

This is a patch for Python 2.3 for proper thread/signal behavior 
similar to  <https://sourceforge.net/tracker/?
func=detail&aid=960406&group_id=5470&atid=305470>. (This isn't 
one of the patches attached to the patch ticket, its the changes that 
mwh made in the CVS revisions listed, plus the further corrections 
in later revisions of the affected files.)