While config.h is generated, it is only included from within st.c to make some things work correctly within st.h.
I would suggest changing things a little:
- Put an include of config.h into src/avro_private.h
- Include avro_private.h into all .c files.
- Not sure if the values from config.h are needed in any of the tests or examples ... I would hope not though and that this is fully insulated from being visible within anything exposed by avro.h.
Given some feedback, I can readily prepare a patch.