Compiling elspy on Debian unstable

I'm trying to compile elspy and Exim 4.30 on a machine running Debian
unstable.  The compilation completes without a hitch, but the resulting Exim
binary dumps core when receiving a message.  Even more puzzling, when I run
it under GDB to find the exact location of the segfault, it doesn't dump
core, but delivers the message without problems.

Right now I'm wondering if this is happening because Debian uses a shared
library for Python; perhaps GDB loads the shared library at a different
location and the segfault is therefore avoided.  Has anyone seen anything
like this?  Anyone have suggestions for debugging the problem?

--amk