Silence class vs. struct warnings (vec)

[pinskia@gmail.com]

> On Dec 5, 2013, at 1:33 AM, Oleg Endo <oleg.endo@t-online.de> wrote:
> 
>> On Thu, 2013-12-05 at 01:11 -0800, pinskia@gmail.com wrote:
>> 
>>> On Dec 5, 2013, at 1:00 AM, Oleg Endo <oleg.endo@t-online.de> wrote:
>>> 
>>> Hi,
>>> 
>>> When building GCC on OSX with its native XCode/Clang tools, it outputs
>>> quite some "struct X was previously declared as a class" or similar
>>> warnings (-Wmismatched-tags is enabled by default).
>>> 
>>> The attached patch fixes a mismatch in struct vec_prefix when referring
>>> to struct vec.
>>> 
>>> Tested with make all-gcc.
>>> OK for trunk?
>> 
>> What is this warning trying to do really?  I think this is a very bad warning as points out standard code for no reason. 
> 
> I think the answer is here:
> http://llvm.org/bugs/show_bug.cgi?id=11632

Except we don't support compiling GCC with microsoft's broken compiler. So again why make this change for broken compilers that is hard to support in the first place?

> 
> Cheers,
> Oleg
>