How to clean up after a C extension module is destroyed?

[Alex]

Another question which I'm just sort of curious about: If in a C
extension module I malloc some memory, and for some reason I expect that
module to subsequently be destroyed, is there any way to ensure that
that memory will be free'd?  

Alex.

-- 
I'm not an outlier; I just haven't found my distribution yet.  
--- Ronan Conroy

To succeed in the world it is not enough to be stupid; you must also be
well-mannered. -- Voltaire