[patch,gfortran] Fix PR17917 - module equivalences

[Paul THOMAS]

Steven,

> + const char *module;
> 
> Could you explain what this is for? I see we write it and read it,
> but it's not used for anything else. Needed for follow-up work?
> 
I have implemented the use of module but it does not eliminate the duplication of the declaration of module equivalence unions.  There is something wierd happening upstream.  I will investigate tonight.  I hope to tie up the package over the weekend.

Paul