I had a strange issue few days ago compiling a program against libax25. Compilation was OK, no error messages nor warnings but running it (a Python module written in C) didn't start claiming a missing reference to inflateEND. Was also strange, that other applications using libax25 were OK without such message.,
Finally I found it was a so called underlinking issue. This is a good summary of the problem:
http://wiki.mandriva.com/en/UnderlinkingIn my case the solution was to rebuild libax25 with the -lz linker switch.
It may affect other extensions too and the extension building process.