privat/nit — pull request #368 by privat (2014-03-26 13:37:24+00:00)
Title: Fix ffi null service

With nitg-g, the linker could fail when the same two piece of code will be in distinct files,
since the #ifndef trick does not cross compilation units.

This PR is just a workaroud where we use a global flag to avoid multiple definition.
While it works (thus is an improvement) it is ugly and broke the separate compilation concerns.