GCC warnings for unused global variables

[Kean Johnston]

> It's implementation-defined what is an 'access'.
> 
> It looks like it's useful to define initialization as an 'access', for
> exactly this case: rcsid, or in general magic code that looks at
> object files.  So, let's do that.
Careful.

If you mark initialization as access, and that makes the warnings go
away, we'd lose some considerable value to the warning. Just because
this rcsid is such a PITA, doesn't mean it shouldbe be warned about
if that's what the user wants, but since its initialized, if that makes
the warning go away that's bad. Same for any other variable that's
initialzied but not used (in static scope of course).

Kean