Fixing namespace issues for variables

[Roland McGrath]

> Well, portable code can't use &stdin, because it's simply not valid with a 
> traditional definition of stdin as (&_iob[0]).  The standard says the std* 
> macros are expressions of type "pointer to FILE", with no requirements on 
> being constant, able to have their address taken, etc.

OK.  But &foo is an issue for the other ones you're proposing changing.