How to make sure that there is no undefined references to a module

I am trying to develope a little module of my own, the modules compiles fine. But to make sure that my modules has no undefined references, I added this to the Makefile :- RLM_LDFLAGS = -Wl,--no-undefined I tried the idea on one of the simplest module which comes with the sources, rlm_exec, but after that the module then failed to compile, having lots of undefined references. eg :- :273: undefined reference to `radlog' :442: undefined reference to `radius_exec_program' Any advise how should I go about fixing this problem ?