libobjc: Remove Traditional Objective-C runtime API

[Nicola Pero]

> This patch completes the removal of the public part of the 
> Traditional Objective-C runtime API from libobjc.
> 
> From now on, the only supported API is the "Modern" API. :-)

> Nicola, this is causing trouble for Fedora.  The Fedora maintainer has
> been advised by GNUstep upstream to switch to LLVM.

In Cc: there is Richard, the maintainer of gnustep-base, and I would be
very surprised if he wasn't supporting GCC 4.7 and advising to switch to
LLVM for this reason.  As far as I know gnustep-base has the goal of
supporting all compilers and runtimes.

Most likely this is due to a small error in the configure script or in a
file includes in gnustep-base.

> Do you understand what is going on?  Will LLVM keep the Traditional
> Objective-C runtime API?  Or maybe GNUstep will update their software?
> This is very perplexing.

I'm fairly sure that GNUstep will update their software. ;-)

Thanks