Implementation of CFBridgingRelease() on GNUstep

[Daniel Ferreira (theiostream)]

Hi there! I'm Daniel Ferreira, and I'm the student who will be
contributing to GNUstep through Google Summer of Code for the next
three months. I'll be working on getting WebKit to run on top of GS.

That being said, one of the first things I stumbled upon when building
WebKit against GS was the absence of a GS implementation of
CFBridgingRelease
(https://developer.apple.com/reference/foundation/1587932-cfbridgingrelease).
I asked Ivan about how to deal with this and he was under the
impression that in GNUstep, CFBridgingRelease() should be equivalent
to CFRelease(), but he couldn't state that with absolute certainty.

So this is the question: are they somehow equivalent in CoreBase's
understanding of ARC? And if not, how would you suggest this be
implemented? I didn't see transferring memory ownership to ARC being
dealt with on threads like this[1] about supporting ARC on CoreBase.
Also, only GS thread I could find that addresses the function in
particular is this one[2], and it doesn't look like much help either.

Thanks,
-- Daniel.

[1]: http://lists.gnu.org/archive/html/discuss-gnustep/2015-02/msg00021.html
[2]: http://lists.gnu.org/archive/html/gnustep-dev/2015-12/msg00020.html