[Patch] Remove flag_objc-sjlj_exceptions as a User control, move ObjC exception mechanism choices to gcc/objc/

[Gerald Pfeifer]

On Wed, 30 Nov 2011, Iain Sandoe wrote:
> There is really no point in having a flag to control the Objective C (or 
> Objective C++) exceptions [@throw, as opposed to throw] scheme, since we 
> actually only support one scheme for each permutation of runtime and 
> ABI.
> 
> This removes the flag_objc_sjlj_exceptions (or, more correctly, 
> localizes its effect to the ObjC FEs).

Mind documenting this in the GCC 4.7 release notes 
(wwwdocs/htdocs/gcc-4.7/changes.html)?

Gerald