C/ObjC: Fast enumeration for Objective-C

[Nicola Pero]

> * decided that, unlike in the Apple compiler, "for (id object in collection)" is only available
> when using -std=c99.

By the way, I have a slight preference for this solution as it makes the code simpler (and it
makes more sense to me) but I don't have a strong opinion; if someone was to produce a patch
to have the compiler accept that syntax even without -std=c99, for compatibility with Apple
compilers, it would be fine by me. ;-)

Thanks