I made the various static arrays in headers declared as extern and
defined in a separate implementation file, with additional size constant
when necessary (since G_N_ELEMENTS() cannot be used on partially
defined arrays).

Note that this is better than the original implementation, yet I am not
saying this is ideal either. I am not fond of such code organization and
think a better one could be done. But it would require to dive deeper
into this plug-in and I don't want to right now, nor have the time.

At least now it stopped shouting all these warnings!